2004 120,000 miles, will surge

valkman51
0

Asked by valkman51 Oct 20, 2012 at 03:00 PM about the 2004 Chevrolet Silverado 1500 Work Truck Ext Cab Short Bed 2WD

Question type: Maintenance & Repair

When I first start the truck it runs good but then it will surge, run good then surge again. Thought at first it was the transmission but thats not it.  Not sure if there is some sensor going bad or not. No engine light comes on.  Seems ok once the truck gets warmed out.

9 Answers

John Saffrahn
16,295

While driving or at an idle?

2 out of 2 people think this is helpful.
valkman51
0

While driving

John Saffrahn
16,295

Could be a number of things, when was it last tuned up?

1 out of 1 people think this is helpful.
valkman51
0

Well, I changed plugs and wires at 100,000 along with cleaning out the injectors. It does seem to run rough when I first start up then it settles down. Thanks

John Saffrahn
16,295

How long does it run like this, is it seconds or minutes. Also did you put the iridium plugs in it or the cheap ones. The newer General Motors ignition systems use an HEI ignition system for a cleaner burn. They used to have HEI on the distributor systems in the late 80s also and the reason those were marked HEI and the new ones aren't is because all the new GMs have it. Point is that instead of 30,000 Volts the new ones are 60,000 to 90,000 Volts and standard plugs are lucky to make it 30,000 miles some crap out as quick as 10,000. It may be starting to need decent plugs and the bad ones just aren't creating the spark needed while the engine is cold and in open loop mode. Let me know what plugs were used and we can go from there.

1 out of 1 people think this is helpful.
valkman51
0

John, I'll have to get back with on that. I looked at my idemized bill and it doesn't specify. I know the plugs cost me $48.00. I'll have to pop the hood and check but I have the feeling I may have got the cheaper ones. Thanks for all your help.

John Saffrahn
16,295

What is the spark plug part number on that itemized bill? It should start with a 41-*** if it starts with an R then its just a standard copper plug. Also the plugs alone are approximately $7 which for the 4.8 or 5.3 is 8 plugs. So the plugs alone would be $56 + tax. A shop would be closer to $100 for the same plugs. If they aren't AC Delco then its the wrong brand all together.

1 out of 1 people think this is helpful.
valkman51
0

Thanks, I'll check the numbers tomorrow. Silly question but will the bad plugs make the truck hard to start?

John Saffrahn
16,295

Crappy plugs can make it start hard and run crappy while its colder due to the fact that while its cold #1 the air is denser making it thicker and more difficult to pass a good spark through it and #2 when an engine is cold its in what's called open loop mode where most sensors do very little and the rest do nothing. A predetermined amount of fuel is put into the engine depending on where the throttle position sensor reading is and the mas air flow sensor is not payed any attention. This also why your vehicle sometimes smells like gas when its started on a cold and damp morning.

1 out of 1 people think this is helpful.

Your Answer

Add photo

Related Questions

Silverado 1500
Looking for a Used Silverado 1500 in your area?
CarGurus has 169,179 nationwide Silverado 1500 listings starting at $650.
ZIP:

Search Chevrolet Silverado 1500 Questions

Chevrolet Silverado 1500 Experts

#1 tenspeed
tenspeed
Reputation 470
#2 Andrew Olsen
Andrew Olsen
Reputation 460
#3 califcarson
califcarson
Reputation 440
View All

Related Models For Sale

Used GMC Sierra 1500"
986 Great Deals out of 62,340 listings starting at $1,495
Used Ford F-150"
2,597 Great Deals out of 165,861 listings starting at $1,495
Used Dodge Ram Pickup 1500"
850 Great Deals out of 15,245 listings starting at $1,222
Used Chevrolet Silverado 2500HD"
539 Great Deals out of 39,845 listings starting at $3,500
Used Toyota Tundra"
520 Great Deals out of 26,209 listings starting at $2,995
Used Toyota Tacoma"
572 Great Deals out of 21,959 listings starting at $2,199
Used Chevrolet Tahoe"
987 Great Deals out of 33,072 listings starting at $2,500
Used Chevrolet Silverado 1500HD"
23 Great Deals out of 321 listings starting at $5,550
Used Chevrolet Colorado"
227 Great Deals out of 6,021 listings starting at $3,300
Used Chevrolet Silverado 2500"
10 Great Deals out of 363 listings starting at $3,995
Used Chevrolet Avalanche"
334 Great Deals out of 6,119 listings starting at $3,999
Used Jeep Wrangler"
1,004 Great Deals out of 45,508 listings starting at $1,800
Used Ford F-250 Super Duty"
646 Great Deals out of 34,960 listings starting at $2,500

Used Cars For Sale

2014 Chevrolet Silverado 1500 For Sale
264 Great Deals out of 83,094 listings starting at $18,995
2013 Chevrolet Silverado 1500 For Sale
405 Great Deals out of 7,378 listings starting at $14,524
2012 Chevrolet Silverado 1500 For Sale
302 Great Deals out of 6,234 listings starting at $8,495
2011 Chevrolet Silverado 1500 For Sale
388 Great Deals out of 7,487 listings starting at $9,995