Ford F150 knocks and misfires bad all of the sudden

If you replaced your engine from another from another vehicle and you know that engine was running good the problem is in the exhaust system the catalytic converter or exhaust manifold is clogged. Start vehicle and let it idle for about 15 to 20 minutes and check manifold and converter if either one starts to glow red it is clogged.

also did you use any thing off the other motor like coils ignition system, wiring harness etc

and why pay or ask you to pay if hey couldn't fix it

I dropped the exhaust off of it today and let it run off the manifolds but it made no difference.I then unhooked the negative wire from the battery and ran a jumper wire from the positive side of the battery (while leaving the positive wire hooked to the battery)and let it sit for 10 minutes to clear the ECU.I then turned the key to the on position and waited 10 seconds and started the truck.It made no difference. I am using the wire harness that came with the donor engine.I just left it hooked to everything on the engine and plugged it in to the harness of the truck.As for why I had to pay for it,I had a loan on it and still owed 3 years on it and I had to pay for the "repairs"to get it back.And as far as cutting my losses on an old truck it has gone beyond that.This is now a quest for me,an obsession and I can't stop until I find the answer.I appreciate all the help I can get and I thank you all.

Is the knock coming from the top or bottom of engine ? Do this test start engine and get as close as you can to the oil pan if knock is noticeable louder the rod bearing need to be replaced. You can replace rod bearings with out removing engine just have to remove oil pan.

The knock I have is a spark knock caused by the timing being off which is causing a misfire condition.It is basically as if you turned the distributor of an older engine counter clockwise until the engine begins to sputter and knock and misfire but not far enough back to the point of backfiring.That's where my engine is at.The knocking is in the top of the engine by the way.Thanks for the suggestion though.it is appreciated!

if the motor is running the same as the other one and you did not keep any of the coils then i would look at what you did not change ie maf, map,computer,vacuum lines that are on the fire wall . fuel pressure ground cables.

I will look into the ground cables as I have already changed all the other items you suggested. I also purchased a code scanner and I am hoping that it will give me some fault codes to follow up on too.Thanks for the advise.

I did the same thing once and found the fuel two fuel injectors to be faulty. With the truck running pull the plug wires one at a time from the coil pack. Check to see which one/ ones doesn't cause the engine to change. There would be at least one that will not create a change. -This may be the fuel injector you need to check. Pull the upper intake and remove fuel rail. -Check for any visual signs of it being clogged. With the fuel injectors out of the intake have someone crank the engine, they should all spray in series.

I know it's old but at all that I didn't see anything about a fuel pump that's crazy man

I have a Ford F-150 4 wheel drive it started acting like it not getting gas what could it be?

well im narrowing mine down to now a short in fuel injector wire harnest! im dight on the edge of goig Yota soon!!

Variable valve timing solenoid?

Check the rubber elbow on the back of the intake manifold those spring a vacuum leak all the time

And those engines do not like getting sprayed down for degreasing purposes

I would guess maybe the computer in the truck, cause its still the same one, right ? The 4.6 ran fine in the other truck and now it don't in the new truck. I know its expensive but if u can find a place to have it tested. Or try to change computers from the 97 to the newer one with the 4.6 in it now.

you bent A-Rod. I had the same problem I replaced everything and it's a bent rod that's all do you need to replace the fucking motor bottom line

There is a sensor that is telling the ECM the motor is over heating. There for causing it to shut down 4 of the 8 cylinders. I can't remember the part but I'll try to look it up when I get home from work. My 97 f150 4x4 was doing the same thing an I finally got it to pull the code one time. But this has been a year or so ago. So I'll look back at my tickets an try to find it. But it's just a sensor shutting down 4 cylinders because of a false over heating, so it's trying to save its self.

My intake craked so i replace it my thermostat but now it don't have the power god gave a jack ass what could cause this problem????

Bad pickup coil in distributor

The one with the motor that is hitting on 3 are four cylinders I believe you have a bad pickup coil in the distributor

Mine was running fine and then the next day it's only hitting on 7 cylinders I took it up and had it scanned it says number 3 is misfiring I put new plugs in it I changed the coils and it still missing.... I'm going to try some of these suggestions that was put down by different people thank you all for your advice......

This is definitely your Ignition switch below the collar of the steering wheel column, engine control module on the driver side fender and/or the computer. Pull the computer, you just need to detach the air filter lines to the throttle body and loosen the wheel cover so you can pry the CMD out. Open it up and inspect the circuitry. The big give away is corrosion and a very bad Computer will have a blown capacitor or two. Mine did. That completely shut my truck down til replaced. Get a new one from RockAuto. Second, ignition switch is literally the first relay from your battery. If no start, that’s a good check BUT if you hear the starter try to crank the motor then it’s the ECM (engine control module). It’s a 30 minute swap and a fairly inexpensive part. You’re gonna be pissed if Ford missed that but it won’t throw any codes just secondary issues like TPS, EGR or MAP burn outs (which if it does run while in broken condition will eventually burn out your MAP Sensor every day and twice on Sunday (every 200-500 miles you’ll be replacing it). The TPS in that condition will burn out prematurely too every few thousand miles. One last good thing to check if all this is going on is the coil’s harness connection. Those pug tails will corrode the most and splicing a replacement may be everything you need given the issue is most definitely in your wiring harness I would scrutinize each pig tail (replacements for each available at Rock Auto) for corrosion on the front or bag of each plug and replace as necessary. Fixing your wiring harness and/or primary ignition and engine control components should alleviate the vehicles no start condition. And yes, quite aware it’s 3 years later but I didn’t see anyone give a thorough run down. I saw one gent hint at the computer and he has the right idea between that and the ECM you most likely will have a running vehicle again.

Oh yeah and a computer learns your timing, so that initial diagnostics from Ford makes sense except they should have inspected the computer as a broken computer will give broken outputs such as that timing issue, when in reality a circuit or capacitor has corroded and degraded the voltage which will inevitably throw bad codes and controls. The computer initally receives its inputs in the engine from the ECM and then hands it off to the Computer or vice versa (can’t remember). So basically one passes engine control off to the other once it has spun up and then gone to idle. So again, ECM or CMD (Computer) are your primary culprits. Bad mechanics not checking those first before doing the timing chain. Unless you do a lot of aggressive driving there is no good reason for that to happen anyway with this truck. However the ECM and CMD go bad every 15- 25 years and you’re right on schedule.

Crank shaft senor is bad, or throttle body gasket needs replacing! The code does not come up on diagnostics for the later.

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