About a month ago the truck ('01 5.4 no mods) started "missing". While driving and maintaining speed it would buck and feel like I was driving over 2x4s in the road. I checked out the forum and put in a new IAC and EGR. Truck ran fine...until now. When I first get in and drive the truck while it's cold, it purrs and runs great everytime. As soon as it gets to operating temp, it starts "missing" and buckin' and chuggin'! If I bury the throttle, it roars to life and accelerates like it normally would wide open. I just had the fuel injectors cleaned and changed the fuel filter. I say "missing" because I always thought a miss was a miss and it didn't matter hot or cold, fast or slow, it was always present. I could sure use some fresh ideas. Again, it runs perfectly when cold.

Thanks All

 

I also cleared the ECU by pulling off the negative battery cable, then turned light switch on to drain anything reserved. Waited 10 minutes and drove for about twenty miles. Ran great until it warmed up. Arghhhh!

 

I'm having the same problem with my 95 4.9L 5 speed. I'll be interested to hear what the people think. I have changed the fuel filter, O2 sensor and checked the throttle body (which was surprisingly clean) to no avail. It has good power for about 5 minutes then after full operating temp is reached, a good bit of missing.

 

This same exact thing happened to me....My problem was my #8 cylinder coil(which it could be any of the 8). I believe once it got hot & expanded it wouldn't get a good enough spark for some reason..... I also put that dielectric grease on all my coils.

Hope this helps....OH! if you need a coil, you can get a whole set of 8 at troyer performance for $200. I bought one(1) at the dealership for $75.

 

Are Troyers superior to stock? I've seen that a few of the people on the forum have these.

 

My 98 would miss after about 2 minutes, but only if the airconditioner compressor was running. I repositioned the wire bundles so that they weren't touching the air conditioning accumulator (in rear passenger side of engine compartment). One bundle was near the top of the accumulator, and the other near the inside of the wheel well. I used wire bundle ties to hold them out of the way. I read about it from a poster named PKRWD
Now I can run the air conditioner/defroster etc, and no miss, & gas mileage increased from about 10 to 16.5 mpg. Before I tried this fix, I changed spark plugs, wires & both coil packs, to no avail.