Hi all,

I have a 2003 f-150 4.6 screw 2wd automatic, I drove from New Hampshire to North Carolina in under 3 days, passing through Virginia I came to a stop, and the truck started to buck and seem asthough it were going to stall, well i had no choice but to drive to get home, so on the way home about 400 miles into the trip I pulled over to sleep, the CEL came on, and the truck continued to miss and buck as it did previously, after about 2 hours of idle time (it was 90 degrees at night a/c was nice) the light went off, and i continued to drive the rest of the 600 miles with no light on, the truck still stayed the same no light.

Now, when i got home as quick as i could i bought a scan tool, no light on i plugged it in anyway, read the codes only one came up which was cylinder 2 misfire, so i replaced to COP, cleared the code, and drove it, it was fine till i stopped at a light, and it still stayed the same. I cleaned the MAFS with specified cleaner, the IAC and checked everything over, I tested all the coil packs by unplugging one at a time, with the truck in drive foot on brake(e-brake too) still misses and bucks like it wants to stall, but hasn't, is there anything that im missing, I kinda rode her hard for 33 hours, a/c was on the whole time and trafic was unbearable, the freeway was nice she rode perfectly, it was just at stops, and creeping speeds where the truck would act this way. Any help is greatly appreciated thanks.

 

I must assume that before you replaced the #2 cop,you pulled the plug and looked at it.
This sounds eerily like a "dead" cylinder.Not in the sense that its shot,but either not contributing to the balance of the rest of the engine,or weak compression(which will exhibit the same conditions)
You could have something as simple as a clogged injector....The fact that its most noticeable at idle makes me wonder.
Id do a good compression check,and see if there are any abnormal results.
Im just shootin in the dark here

If you do a compression check,look for uniformity of results,not necessairily a high figure.

 

thank you for all your help, but as the idiot that i am, i replaced the wrong coil pack, i replaced number 3 instead of 2, runs like a champ now, again i appreciate all your help, and extending your knowledge out to help a fellow ford owned



thank you.

 

Thanks for letting us know that you got her running like new!