I have a 95 F 150 with a 302 5 spd. When you come to a stop it will shut off, and when you are going down the road the truck will start bucking. It doesnt do this all the time. I have changed spark plugs, cap, rotor, wires, fuel filter,map sensor, tps sensor, egr valve, clean throttle body, and the idle air control.

 

Welcome to FTE!

Looks like you have really thrown some money into this problem. Has the CEL come on at any time? If so, have you pulled the codes? Could be the TFI. It's located on the drivers side near cowl. It could be going bad. It could also be that the TFI is overheating. Check for a good grounds. also check the screws(fasterners) to the TFI for corrosion.

I'm a newbe too. Hopefully some other veteran FTE folks will chime in later with some other suggestions.

Keep us Posted!


EDIT*** Here's a link to a Post here on FTE concerning the Driver-Side Fender-Wall mounted TFI
https://www.ford-trucks.com/forums/3...fi-module.html

 

...there are at least three different threads on this very issue and zero end with an answer. So here I sit--having the same issue...changing the same parts and ending up with no positive results. ugh

 

Welcome to FTE.

Could you elaborate on the problem you have. Is it exactly as stated by the OP? Have you pulled codes? Let us know all problems, repairs, and troubleshooting you have performed, and we'll try our best to help you out.

Also, is this on the same vehicle as the OP listed, 95, 302, standard trans? Mileage?

 

Truck began bucking at 40-42 MPH, then the problem disappeared for a few days. A week later it had trouble at idle and I was able to "gas it" into the local garage.

I assumed (bad on me) that it was simply a fuel filter or pump problem. To date they have changed out the air and fuel filter. They have cleaned the EGR valve, throttle control, injectors, and replaced the MAF sensor.

They were about to declare victory...but as I was about to drive away--it stalled. I am waiting for a call-back and will ask about the codes. At this point I am going to recommend they check the ignition coil and idle control valve. Initially they assumed it was a vacuum leak.

1995 F-150, it has a Jasper remanufactured engine replaced at 188,000. It is currently parked at 202,000. I recently purchased the vehicle and so I have no further history. It's a .302 automatic with two tanks--only the front one is operable and I just had it replaced due to rust.

I will be sure to post again should the local garage be able to diagnosis and repair.

Thanks for asking.

 

Not sure if the fix applies to the 302 or if the 4.9 was the only engine with the EGR issue, but there are a few threads with a write up about how to create an EGR valve restrictor plate with sheet aluminum and two EGR gaskets. Might be something to look into, if the EGR is flowing too much at cruise it can cause stumbling or "bucking" at highway speeds.

As for the intermittent stalling and other issues, I would suggest opening your ECM cases and checking for capacitor leakage, it's a very common issue and before you drive yourself crazy it's a simple enough thing to check off the list. And if they are leaking, then you've found at least one issue.

 

Will pass it along...and yes, I am familiar with the EGR Valve solution...always perplexes me why the folks just wouldn't replace the valve itself vice manipulation?

 

**Update**

shop alleges the dirstributer cap was the issue. They have logged 50 miles on the vehicle and claim no issues. We shall see...I am absolutely NOT confident after reading the various threads on this site. Many of which changed out the dirstributer cap very early on. I wagering on having to replace the ICV, coil springs, and the ECM before it is over. Finally--service writer had no knowledge of thrown codes and the wrench was gone for the day. More to come...regardless.

 

Approx another 50 miles...issue has not reappeared. At this point--I am guarded, however optimistic. Fingers crossed.

 

I have a 94 f150 5.0 4x4 auto 4sp has 151k. got it and was running great and I replaced plugs and wires and here I crossed over 2 wires and it was bucking and missfireing like crazy so I put them on currently and it still dose the same thing so I replaced. EGR valve tps sensor plugs wires cap rotor ICM module coil pack cleaned ICV and fuel filter adjusted timming to 10. still bucks carries on start up fast idels good. when warmed up it start up expecially going up hills when it gos into over drive it gets really bad I have no idea what it could be any help or suggestions will be appreciated. Thanks

 

best of luck-- we are over 1000 miles since our issue...has not returned, thankfully.

 

since the problem started right after you changed plugs and wires i would go back and triple-check my work ( i know you said that you corrected 2 crossed wires, but the problem is still there). check that you have the firing order right and the direction of rotation right. check that the plugs are snug and the wires are snugly seated on the plugs and on the cap. check that the cap and rotor are properly installed.

it would be a good idea to run your engine in a dark place and check to see if there is any cross-firing going on between the plug wires.

if you still have a problem after this then check for codes.

 

I took it to get codes checked but the engine light wasnt on and the garage said its not reading anything showing its running perfect. Well I just went out and checkes for spark and cylinder 5 spark plug is sparrking bright blue all around it and sparking from the sides of the coil could it be a bad plug?

 

you can check that easily by swapping plugs, but i would suspect the wire ... not seated properly or the connector not connecting with the plug.

 

Ok I put a new wire on stoped the sparking around it and checked plugs they r good but it still keeps bucking and missfireing a little less but still constant could it be a faulty coil pack?