I had made a couple posts on this in the gen 1 250 SD section so please forgive me. I have a 2002 F250 SD with a 5.4. It started to have a small miss upon acceleration and has gotten worse. it only misses on acceleration. Idle is smooth and say if you get up to speed and ease off the throttle it will run smoothly. I have replaced all the plugs, 1 coil and 1 injector. All coils and injectors ohm out good aka the resistance is within spec on each one. I got the truck in June with 78,000. it now has 82,000 and have run 3 bottles of injector cleaner through it and relaced the pcv. It isn't throwing a code as far as the check engine light coming on but my son is bringing his analyzer by tomorrow evening but I am wondering if anyone has had a similiar problem. Thanks, David C.

It sounds to me like you may have a weak coil on one (maybe more than one) of the cylinders. What you describe is what the 5.4 did in our Expedition...The CEL never did come on while it was like that...

It's a coil, my friend. It's just a matter of tracking down which coil is the problem. There is no guarantee whatsoever that you computer will throw a code and tell you which cylinder it is. I had 2 bad coils on my last round, and cylinder 4 and cylinder 7 were my problems. Start in the back to save yourself time - the heat back there causes them to fail first.

Ryan

Many mny thanks my great friends. i will replace the tps just for good measure but I will get a new coil or two and start replacing them to track down the bad one. I did a resistance check on them but I know under load and heat problems do pop up. I will post the answer once I find it so maybe one day a guy may come along and read it too and have the help of two guys like yall. many thanks and God bless yall daily.

Good luck! Post up which cylinder it was that you had problems with once you find out. I would be curious to know if the back ones really do fail that much more often.

Ryan

The back ones DO fail more often.

It was #3. Bad coil. I appreciate yall so much. I just came in from my shop and made sure to let yall know. Thanks guys. god bless yall very much.

read this page

http://www.automotiveforums.com/t532866-discuss92_merc_bucking.html

Mil1ion said:

read this page

http://www.automotiveforums.com/t532866-discuss92_merc_bucking.html

Click to expand...

How does this relate? What did I miss?

None of the dealerships service dept have any knowledge of this and thus no TRUE REPAIR procedure.

I am personally battling this Intermittent stumbling on my 92 Marquis 4.6L

No one one knows the TRUE reason for this stumbling BS.

I was trying to convey that by submitting a link to the issues people have and that fix mentioned may not work.

Hmm, it seems that he resolved the issue with changing coil #3.

Ryan

That's what I got....but I thought maybe I missed something.....that has happened many times before