I have a 01 ext. cab and it is an auto as well. Coming off the line it has a stumble to it. It is also noticeable when on the interstate around 50mph and excellerating uphill or in traffic it does the same thing. It consistantly get 19.7 mpg. The dreaded check engine light is not coming on either. Any idea what could be doing this?

Thanks.

 

https://www.ford-trucks.com/forums/s...hreadid=124144

 

Have a 97 with a 4.2 having the same problem at 75000 did a plug change with the same brand plug and the best set of wires napa had. problem went away except for a stumble some times but it's coming back !!Read a post somewhere in the v-8 section that he was having a problem almost identical to mine he said that ford said one of the coil pacs went weak and said the replacement worked great. but he thinks some more may be going too be cause it sometime stumble.

 

pull your zip tube off the throttle body and clean the inside of the throttle body with choke cleaner they have problems with the inside gumming up, resulting with the same problems.

 

Bones I tried that .It idles better after that but still the same miss under load at lower RPMs Thanks for the reply!!

 

Alright, the root of my problem was a bad coil pack. It had gone bad and fouled out the plugs on cylinders 3 and 5. How about that. On a truck with 47K. My ford certified warranty with $100 deductable would pay for roughly $80 of this repair. Coil pack 86.55 new plug 4.85 diagnosis $45 and labor $45. According to the service advisor this is not uncommon for these engines. Then why did'nt they fix the problem at the factory? I guess the service and parts people have to eat. lol. I still love my ford trucks though.

 

I have a 99 ford e 150 with a 4.2 liter in it and I am having the same problem. One question for all, is it possible that it is a bad heated oxygen sensor?? Just thought I would ask..

 

Update Went a bought a new coil pack at auto zone $75 put it in and now the stumbling off idle has stopped and underload has stopped to a point . It's acting like when it was new. Kind of jerky as it revs up. I have been told that is caused in part to the dual runner manifold.Have about 76000 on it 4.2 v6 5Speed stick.

 

For what its worth what is a zip tube ?? And I would like to know how do you check a coil pack to see if its not opetation correctly?? And I checked a 2003 e150 4.2 liter and noticed that the coil pack had been relocated to the side of the intake manifold as apposed to the top of the manifold, like that of the 99 4.2 liter How does the dual runner manifold work???

 

I just bought a 97 F150 4.2, 5spd 125,000 miles. It needed a new fender and door, but I have been driving it for the last week as is. I love the truck (as compared to my 93 Civic I was driving, plus it should haul my trailer instead of my father's truck) Anyway, the truck is doing the same thing as everyone elses in the thread. Under a load, or going up a hill, or just getting on the throttle will cause the engine to stumble. No engine codes yet, but I am not sure if the check engine light works, should it come on at the ACC position with the key before the engine is started, or not? It doesn't. I have searched threads on this forum and others and talked with two mechanics and been told to run injector cleaner and high octane, replace the fuel filter and that it could be one of a handful of sensors, or the coil pack. I find it hard to believe it is a sensor or the plugs since it drives and idles so smooth under no load. I have tried the injector cleaner in a tank of high octane, and replaced the air filter, changed the oil and fuel filter. With no check engine code, I am just guessing at repairs, and most of them are right at a hundred bucks per pop. Any ideas where to start, I am reading my Haynes manual tonight to see what the troubleshooting says about the problem. Thanks in advance.
~Chad

 

I was told that the coil pack was weak on mine between two of the terminals. Thier is supposed to be an even amount of resistance between them, did not get into that with them, and mine was not meeting the load generatated by the engine so when a load was applied it stumbled. I got a new coil pack, wires, and motorcraft platinum plugs and it runs like new.

 

It seems the genius that sent the car to the auction had pulled the dash apart and removed the light from the dash in the check engine light. I put it back in, unhooked the battery and then went for a drive. Not to long into the drive the check engine light lit up, and I took it to Auto Zone. It had 2 codes, not sure of the number but it was a misfire on cylinder 3 for both codes. Guy at "the zone" told me to check the plug wires at both ends then replace them and the plugs. He sells Bosch wires that are kevlar coated. 65 bucks. I intend to try that tonight I guess. Anything else that can cause this misfire in the ignition system? Thanks, Chad

 

This reminds me of a problem I had last year in my 97 4.2 V6. It was stumbling as you all described. I changed coil pack, wires, plugs and it seemed to help but the problem would always surface again. I must have changed my plugs and wires several times over a few months until I decided to check for cross-fire around the wires. I checked it at night and sure enough I saw my wires cross firing as I revved the engine. I tried taping the wires, no help. I finally changed the platinum plugs and used regular type plugs. The stumble is now gone and the cross-firing stopped. Anyone understand why this is happening?.........really weird.....

 

Pcdocta.....check out the thread in this forum for best plugs. There is an interesting discussion in there on copper vs. platinum. One of the guys indicated that there were different plugs for different polarities on the opposing banks. I am going to keep following that thread to learn what I can.

 

I think I have the same problem? I have a 97 E-150 V6. While driving, the engine will gasp for power and my van will jerk really hard. Sometimes it will gasp for power once or several times every 3 - 9 seconds, just once or twice and nothing - it's random. If I'm driving on flat roads the engine will perform pretty good, I can accelerate a bit but if I'm going uphill, I have to speed up as much as possible and move over to the right lanes because the van will start to jerk and I lose speed ( I always end up in the granny lane – if I don’t move over I get a lot of ugly looks and horn honking). The best way for me to describe the jerking is like when your driving a stick - if you pop the clutch in and out from a stop but not kill the engine (like a rookie learning a stick) the vehicle jerks really hard. All this happens while driving.

A Ford dealership performed a diagnostic and recommended I replace the plugs, plug wires and ignition coil (these coils are expensive) – replaced all three and it didn’t solve the problem! The check engine light is on again also. A friend who is a mechanic taking certification classes at our local junior college took my van to class as a project. He believes one of three wiring connections just below the transmission dipstick is coming loose. After I got my van back it performed okay for a while but starting acting up again.

Any thoughts? I don't want this jerking to cause other problems to my van - damage the trans, rear end, engine mounts etc. and it needs to get fixed. I installed platinum plugs, Kevlar wires, replaced 2- O2 sensors and have an extra coil(ouch). I’ll check the coil pack, cross firing at night, zip tube off the throttle body and try injection cleaner. If I have to install genuine Motorcraft plugs and wires – I will. Ford wants to perform another diagnostic to try and find the problem at my expensive and private shops say it could take about 3 - 6 hrs to possibly find the problem. HELP!!!!

PS: Is it possible for me to check for codes and if so how?