Rough Idle Issue


Asked by Feb 14, 2013 at 11:35 AM about the 2003 Dodge Ram 1500 SLT LB

Question type: Maintenance & Repair

I have a 2003 Dodge ram 1500 SLT with the 4.7ltr engine that has 190,000 miles on it. It was idling real rough
recently so I cleaned the throttle body  out and changed out the idle control sensor. That seemed to fix it and it was
running great until a few days ago  when I noticed that the idle was was getting rough again. What could be
causing this? Could it be the fuel pump possibly since I do have a slight hesitation sometimes during

33 Answers

No on the fuel, pump, this is ringing a bell but let me do some digging, oh wow 190K ?? That's high for sure but, hows the maintenance been over all that you know of? It makes a difference whether this is going to be chasing the tail or something else, meaning if your the original owner and tell me the truck been to the doc on a regular basis, OK, if you just bought it and know nothing about how the maintenance that's been done, well that's bad... Follow ??

25 of 25 people found this helpful.

I bought the truck when it had 15,000 on it. Most of the mileage is highway mileage going to and from work. I have been good about the maintenance getting the oil changed every 3-5000 miles and two tune ups done on it. I also have have kept the shocks maintained and transmission and differitional fluids changed. The only major problems I have had with this truck was the air conditioner compressor went out once(expensive repair there) and it hashad two heater cores go bad on it.

4 of 4 people found this helpful.

a few more fresh sensors wouldnt be too bad,how about a throttle position ,plugs ,clean the mass air flow with windex ,all will help.connector cleaning also

8 of 8 people found this helpful.

Windex?? Your not saying like clean the windows type Windex are you, 7Jim?? But to JonH, that's real good news. The air conditioners were an issue with that truck for some reason, have heard that many times. When was the last time you changed the fuel filter? And when you cleaned the throttle body, this was something you have apparently done before and with something like CRC throttle body cleaner?

3 of 3 people found this helpful.

You also mention that you changed out the idle control sensor, so feeling fairly confidant that this is not something you do for fun, the truck was idling bad which caused you to clean the T.B. and then change idle sensor. Who thought there might be a problem with the idle sensor or was it just a thought on your part. I am just trying to reverse engineer for lack of a better explanation, so I can better understand the issue, that caused the sensor replacement to begin with and I hope you didn't clean the T.B. with Windex... no offense made as maybe it works but I sure haven't heard of it least of all done it to any of my vehicles. Or, maybe their is a actual product made by Windex for T.B.'s ?? I up to learning anything new... and I am not joking,

5 of 5 people found this helpful.

iregal, slow down,i bet you hear that alot lol,, i say the maf not throttle area,

2 of 2 people found this helpful.

I cleaned the TB with TB & Carb cleaner, I have never had the fuel filter replaced since the filter/pump is all in one. I had the idle sensor replaced before several years ago by my then mechanic when I had this problem which was worse then because it was dying when I took corners or came up to stoplights/signs. So when I checked it out to see if it just needed cleaned the TB was dirty black so I cleaned it and the old sensor, problem solved so I thought. Several weeks later the problem came back so I changed the sensor and the truck ran like brand new for several more weeks and now it is beginning to idle rough again. I am hoping I can figure this out without having to take it to a new mechanic and pay through the nose to find out it is something simple.

5 of 5 people found this helpful.

Yep, MAF and nope to the Windex air flow sensors are the last thing you want to mess up.. And no I don't hear that a lot, but I'll consider it. And I was, Jon, looking at what you said about Dodge having the filter with the pump in the tank, Mopar.. You know Jon, I have to say that something like this issue your having can be so many different things and just maybe with the miles even being highway and all, just maybe it's time to replace that filter, put if, and I haven't gone so far as to look into how difficult it is to get at that pump and whether you have an access door making it easy to get to, or if you have to drop the tank, but with out hands on diagnostic, like fuel pressure check and even a system scan from the control module end of things, it's really impossible to just honestly say, well just do this and your fixed. It's just not that simple, contrary to what a lot of other guys are going to tell you. You sound to me to be mechanical, so with that said what I have found is some vids you can look at about replacing that filter, because I'll bet it's way past due as far as manufacturer would suggest replacement. So, my suggestion is to have a guy with the right equipment run a complete system scan and see what shows, fuel pressure test which could help determine if there is a lack of flow, the thing I found interesting and I thank you for the complete info, is that part where you said you had problems coming to a stop and taking corners, that's interesting, maybe fuel pump.. it's only guessing and that really is all anyone will be able to do frankly, but I guess I'll hear about that comment to, and I do understand about paying through the nose and that's why I bought my own system scan equipment as I have a lot of performance cars and I needed something to cycle ABS brake solenoids so I could do a complete brake fluid flush and I got tired of paying for what I knew how to do. Look at a tool by AutoEnginuity OBD2 (OBDII) Scan Tool is a professional Windows-PC diagnostics scan tool for all OBD2 (OBDII) compliant vehicles. Non-OBD expansions, maybe something for the future or interesting anyhow and this is what I bought and it's great and I don't need any body to scan my cars for me anymore, and then the fuel filter, I'd think about that and the system scan, so take a look at these vids and then you will need to make your decision as I am positive that I am not going to be able to say Jon change this and that I'd be right, because it would be hitting and missing and guessing without hard facts or hands on, and really I do wish I could help you and maybe one of the other guys own a truck like yours and had the same problem, but I am wasting your time and I'm sorry so these are vids about that pump, some are good and some are crap but this area look around and see what you can find and the quality of who made the vid, I just heard him in the vid say, and here is where we lower the tank, yikees, that answers one question and I am only listening to it... I again am sorry I can't help Jon

2 of 2 people found this helpful.

my truck in the morning when i started it the idle would go up and down then it would be ok,but after awhile when driving the idle would drop from 2000rpm down to 1500 rpms and back up,i changed the TPS throttle position sensor and now it works just fine.

8 of 8 people found this helpful.

I'm gonna help all you guys out. The symptoms could be caused by all of the sensors, fuel pump, etc. but in my case it turned out to be in the wiring harness directly behind front drivers side tire. Can get too it from underneath truck. I accidentally figured this out after changing everything else. I'm sure same problem with your trucks

21 of 21 people found this helpful.

Which harness Buddy, the rectangular one or the oval one? Thanks, Ed

10 of 10 people found this helpful.

My 2001 Dodge Dakota truck starts up in the morning and runs rough until it warms up then its fine have replaced all 4 sensor and did a full tune up what else can it be?

7 of 7 people found this helpful.

Well I have the same problem as Jon with the rough idling n right now n I have also been through two heater cores with the exact same year, model, n make of that truck only thing I've had done is new spark plugs put in n fuel pump replaced n that didn't stop mine from dying at all so should I get some sensors replaced? Or the wiring harness buddy talked about?

3 of 3 people found this helpful.

I have a ram 1500 hemi 5.7. 60k miles..i got it 4 months ago. It recently started acting up. When i drive like at 40 mph then let go of the gas and let the car roll, i hear a funky noise like something ticking...then when reaches like 20 mph, it goes away.... and i do not feel or hear anything during acceleration... only when i depress the gas pedal. I took it to the muffler shop and nothing.....i took it to pep boys and nothing.....i took it to a mechanic and nothing...nobody seems to know or hear the noise i hear. Also when i turn the car on i idles a little rough with a slight vibration...enough vibration to move the seatbelt buckle and tap against the inner side pillar. could it be lifters? Valves? A. Vacuum leak somewhere? I have no idea.....someone please help

9 of 9 people found this helpful.

I have the same problem with my 2004 Ram 1500 4.7. It has 310k on it, fuel pump and filter changed in Dec 13, plugs and coils replaced 2 months ago, replaced the IAC motor and TP sensor, crankshaft and cam position sensors, and cleaned throttle body. Changed oil and filter every 3000 miles, ensured fluids were always full. Trying oxygen sensors next, then checking the fuel pressure and injectors next. Changing the vacuum hoses this week.

6 of 6 people found this helpful.

I have a 2002 dodge ram 1500 I am having a problem with my truck starting after driving a hr or so someone took me they had same problem itwas injector #7 before iI start taking my rack n injectors apart dose anyone know if this can be #7 injector thanks

6 of 6 people found this helpful.

I have a 2009 ram 1500 4.7l v8 bought used with 84,000 miles and shortly after I bought a hypertech max programmer it started throwing codes it starts up normal cold or hot but soon as it warms up it drops down to bout 500 rpm. And then Christmas day it wouldn't shift out of 4th gear (its automatic) pulled over on highway hooked up programmer and said the shift solenoid cleared it and its only came on once since then. What should I do its really starting to drive me nuts?? I cleaned throttle body, tps, and mass air flow, also cleaned air boxes and tube. I'm fixing to buy spectre cold air intake and new tires hopefully will make a difference i hope my computer isn't going out warranty's out on the truck. It has 111000 miles on it.

4 of 4 people found this helpful.

I have a 2001 Dakota 4.7 with 211,780 miles. It began to have trouble starting after siting about an hour, would have to try 2-3 times. I checked the fuel pressure with a gauge, had o psi after siting. 32 psi after started, and held close to that when I punched it, and at 90mph. I was told that it probably had leaking injectors even though I did not see any dark smoke when I started it. Then I replaced the fuel pressure regulator. Problem solved. ( note) this regulator is not available from the dealer or most supply stores. I found several on line at Ebay. The reason for this is that it comes as part of the fuel pump.

3 of 3 people found this helpful.

I have a 2005 hemi 1500 with 140,000 I had a problem with my parking lights not working. All others worked fine, turns, hazards, uppers, lowers. brake, reverse. They all work fine. was told by mech to change out fusebox. 2005 model plugs are up and down with clips holding the wiring to the fuse box. 2006 and later the fuse box was tilted so the wires were not up and down. I cleaned the fuse box after easy disassemble (with wd40) and put back the plugs and made sure they were securely attached. The running lights now work perfectly. Maybe I should have used dielectric grease for the connections however this was a half a year ago and it works fine. (~)^(~) = smug

2 of 2 people found this helpful.

I have a 2003 4.7 1500 I'm having the same problem as Jim2001 my RAM starts up in the morning and runs fine for 20-30 seconds then it starts idling up and down like it wants to shut off, then with no assistance it starts idling fine but hesitates when I push the pedal to go and will be fine the rest of the day, could this be a catalytic converter issue? Have had the up and down stream O2 sensors replaced. what else can it be?

18 of 18 people found this helpful.

Rdoug...I have the same exact truck and the same exact issues. I've replaced the TPS, IAC and cleaned the throttle body and the issues still remain. If you find the cure, please let me know. I will do the same. Thanks

7 of 7 people found this helpful.

rough and kenneth, I have the same truck, 116k miles. was having the same problems, changed the plugs and it got a little better, but then got worse than before, so started changing ignition coils. I had a couple of cracked coils and 1 discolored coil. finished changing them earlier today and so far so good. between the coils and the plug to my max airflow being loose I believe u have solved the problem. a little background. the problem started with a rough idle and the truck acting like it wanted to die. the gages would sometimes flicker. it progressed to losing power and not wanting to take off when I first pulled out of my driveway. fast forward a little later and I I started getting a shake when doing 40- 60mph, I could accelerate through it and be fine, bu my check engine light would start flashing to signify a severe misfire. this is when I changed the plugs and it got a little better, but after a couple days it came back with a vengeance and I would get the shaking and loss of power more often, and every time I climbed a steep hill, and it acted like it was going to die everytime I stopped and idled at a light. after changing the coils it seems to be solved

8 of 8 people found this helpful.

This is a good thread in the fact that I am not alone. I'd like to see a common solution, but haven't read one here. I have a '02 RAM 1500 4.7 2WD, 224,000 miles. Was running rough so I bought plugs, got a code before I could change the plugs. Code - P0304 7 P0308 (random multiple misfires cylinder 4 & cylinder 8. I changed the plugs and cleared the code with coder reader, but also disconnected battery for about a half hour. Engine still ran rough and after a few days, the code came back. A dodge mechanic advised I probably had a couple bad coils. I found a deal on amazon and replaced all 8 and wiped the codes. Engine still ran rough and the code came back a couple days later. I took it into my non-dodge mechanic who read the codes and did a smoke test on the cylinders and found I had a warped intake manifold, they felt that could be linked to my cylinder code errors, so now I have a new intake manifold. Still had rough running engine and same codes. so had AIC & TP sensors replaced. Codes are back and all symptoms remain present. I really don't want to replace every thing under the hood. I'd be nice if the code was a little more specific to which sensor is failing. Any ideas are welcome. thanks.

2 of 2 people found this helpful.

I've been having this problem off and on for about two years now. 1998 Ram 1500, 5.9L, 280,000 Miles. I have replaced plugs, wires, dist/rotor, battery & terminals, both O2 sensors. Engine starts and idles fine for a few minutes, then RPMs drop and the misfires begin. It takes about a minute to die if I don't give it some gas. Codes are O2 sensor high voltage (rich A/FM) and O2 sensor heater. If I clear the codes and the MIL is off, it idles rough and wants to die. When the MIL light is on, it seems to run fine. Mileage is about 10 MPG - I'm hoping I can fix the problem and get that up to 14 MPG at the same time. It runs fine while driving, but if I stop at a light, it will sputter when I give it gas. Sometimes the problem goes away completely, only to return a couple of months later. I live in Florida, so the coldest temp my truck sees is about 50 deg.

3 of 3 people found this helpful.

Jeffbee, I cannot assist with your issue as my codes were all related to P0300 (multiple misfires). Here is an update on my Dodge 4.7. Two shops, one non-dodge, one dodge, have found that I have either a "dropped valve", head gasket issue or cracked head on the passenger side. As the truck has new tires, shocks, heater core and radiator, wheel bearings, etc. etc, etc, I'm going ahead with having the motor replaced. I don't want to rework or replace just the heads as the bottom of the motor would still have 224k miles, ergo a new motor and I hope to be good for a few more years. :)

1 of 1 people found this helpful.

I had this problem with my 2004 Ram 1500 4.7. If I may suggest, check your fuel pressure at each injector. You may have a fuel pressure problem from the pump or regulator. Check each coil and its resistance. I had more problems as mine kept dying. I finally had to replace the PCM $1800, but it fixed the problem

4 of 4 people found this helpful.

After further reading, I checked the O2 sensor heater fuse and it was blown. I replaced it and everything seems to be fine now - no codes after 100 miles of driving. It's hard to believe that fuse was the source of intermittent problems for the past two years, but I've already replaced almost everything else that could cause a problem. Bob: I feel your ache. I have replaced all the ball joints, tie-rods, tensioner &idler pulleys + new belt, steering pump & gear box, pitman & idler arm, front & rear bearings, rebuilt the rear end and all the brakes, had the transmission rebuilt in a shop, and just put new tires on it and had it alligned. There's not much left to replace except the fuel pump, some bushings, and the motor. Mine runs like a champ again and I expect it will for a long time.

3 of 3 people found this helpful.

What's up guys, can someone please give me some tips on an issue I have. So I have a dodge ram 1500 4.7 with 220k miles.when I turn it on the rpm fluctuates from 6000 all the way down to 2000 and sometimes just dies. It also turns off when I come to stop light On the highway it runs fine. I replaced the idle air control sensor and throtle position sensor and still does the same thing

11 of 11 people found this helpful.

I got a code "p0141 which I believe is the oxygen sensor, were is that located? And would replacing the oxygen sensor solve the issue?

2 of 2 people found this helpful.

I don't think it will solve ur problem cause i have a 97 ram 5.9 with 165000 miles on it and just replaced upstream 02, map sensor, idle air control valve and tps sensor as well ran good for a day it's wanting to stall on me now after driving a bit. I don't know what else it can be if anyone can help me please do

1 of 1 people found this helpful.

I have a 2001 ram 5.9 I changed MAP sensor cleaned TB changed TB gasket, plugs, cap, rotor, wires, oil and filter. Replaced Tstat and gasket along with coolant fluid. Plenum gasket is good no leaks. When I let truck idle for 5 minutes it is rough but if I turn on truck and drive without warm up it drives fine. What could be the cause. Checked both O2 sensors both are brand new with only 1200 kms on it. 236000 km on truck itself.


My '98 had rough idle and would die shortly after starting if I didn't drive it immediately. I chased that problem for two years. What finally fixed it (after replacing darn near everything with a wire on it) was replacing my battery.

Check your vacuum pressure, especially at the brake booster where the valve runs a hose to your throttle body. I had a cap plugging a smaller outlet on the valve and noticed it was cracked when my ran started doing this. Also had a problem with the wire harness connection to the EGR valve. Amazon has an OBD2 module for around 20 bucks that works well with the Torque Pro phone app. You can easily monitor your vacuum, intake, sparks, air/fuel, etc and comes with a database of definitions for trouble codes very specific to your car, rather than a generic fault code you get from auto zone diagnostic checks.

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