97 F150 with a 4.2 Liter. 121,000 Miles. Sometimes when I accelerate, the truck will kind of "buck." Sometimes only once and sometimes maybe 2 to 3 times in a row. not sure what a miss feels like but maybe this is it. I also seem to have a loss of power at times. It was hooked to a computer diagnostic and found no Trouble codes. I changed the fuel filter and dumped a $9 bottle of injector cleaner into it and it is still the exact same. The plugs were changed about 20,000 ago. The problem does nto seem to be getting worse or better. Maybe someone out there can give me some suggestions??? Any help would be greatly appreciated.

 

Is it a manual or automatic? Could it be the transmission instead of the engine? If so search under transmission shudder ....there's lots written about that. Hope you get it figured out Phil

 

I had a miss that was due to a small hole in my spark plug wire. Maybe worth checking that its seated properly and doesnt have slices in it.

 

It is a manual transmission. Can a manual shudder?? Sorry I dont know much about this stuff. Also I did think that maybe it could be the transmission, however; I have noticed (Only 3 Times) that it has also done it when I was at a full stop and I rev it up. Like I said it has only done that three times, but it just seems that it is more when I am driving, usually when I accelerate from a stop. it also does it sometimes if I am going down the highway and slow down then accelerate again. Like if I am doing 65MPH in 5TH Gear and slow down to 55, then once I put my foot into it to kick back up my speed it will buck once or twice. All I know is it is driving me nuts. I have even had it into the dealer and of course when they drove it, nothing happened....Anyway thanks for your guy's help. Let me know

 

I also have the same problem. It recently started on my 99 4.6 4x4 with a manual transmission. I suspect a coil problem. It seemd that a lot of people are replacing coils at this age....my truck has 83k miles. Keep us posted on what you find, I'll do the same... I notice mine seems a little worse when the engine is cold...

 

Okay so a few days ago, I went out and pulled all of my plugs, inspected them, they looked fine, then I looked at my plug wires. I should mention that my plug wires are the original and have never been changed. I have 122,000 on the truck. Yes I know some of you guys are thinking, "Well no wonder he has this problem." Haha...Anyway The plug wires seemed ok. But on one of them, right where it plugs into the coil, the rubber protector piece looked "pinched" and bent up a little bit. I tried to work it back into place, but of course this was next to impossible because the heat has basically molded it into place. So anyhow after this, I put it all back together. Then I pulled the wiring that plugs into the coil. Upon looking at this I noticed that the contacts were pretty dirty and had alot of dust in there. So I cleaned it out and put some dielectric grease on the contacts, then plugged it back in. Well I then went for a test drive and what a miracle. I noticed that it had power again and did not "Buck" as much as it had before. It did still buck but not as often and when it did, it was not as noticable. So anyway I think that the actual problem may be that plug wire, which I plan to change soon. But I wanted to let everyone know what I did and what I found, so maybe if it happens to someone else, they can check these things....Thank for your help everyone. if you guys have any more ideas let me know. By the way, does anyone out there agree with me that maybe the plug wire is the problem?

 

Hey guys,

Still no luck fixing this problem. But what I suspect form the last post of mine is the plug wires.. As I stated in last post, after goofing with plugs and wires it seemed to do better for a bit, but now we are right back to its old ways...So I am replacing the plugs and wires tomorrow, But what I was wondering, do you guys think that if changing plugs and wires does not do the trick, What about like the PCV valve? And even an O2 Sensor? Would these make sense or do these usually throw a code? Remember I am getting no Trouble codes.....Anyway, Any help is Greatly appreciated. Thank you all for your time...

 

Well I went over to the Auto Part Sore today and I bought a set of Bosch Platinum Plugs and I Bought a set of Bosch plug wires. Well changed it all out and went and drove the truck for over an Hour, and guess what?? Problem Gone.....Finally..I am assuming it was the wires, I found a few spots on a few of the old ones that were soft and kind of "Bubbled' it was weird. Anyway I got it fixed.....Thanks to everyone that helped....

 

Like I said... I suspect a plug/wire problem ! Great to hear your truck is fixed. How did you like the bosch wires, did they fit as well as the motocrafts? why did you choose bosch over oem?

 

Thanks, I too am relieved that my truck is fixed. So far I really like the Bosch Plugs/Wires. They fit pretty good, but they (Wires) did seems a little "tighter" that the Motorcraft, but once I got them on it all worked out. I Chose Bosch because I had a friend ranting about these and he said they were a good plug and wire, so I figured what the heck. Plus OEM would have cost me a bit more money that I didnt have at the time. So did you end up getting your truck fixed????

 

i did not fix mine yet, while miss is noticable it is not that bad....and since we are about to go on vacation with the truck....i am going to leave well enough alone. I will change the plugs and wires when I get back though......the only question is which brands.... I am leaning to OE ....but I have had good luck with bosch in the past. On the bosch wires, was the boot end the same as OE?

 

Yes the boot end was identical to OE. I was quite surprised actually how exact they were. I think that if you went with the bosch you would not regret it.....I hope it helps