this will be the third time i posted about this, its my truck in my sig it tells what i have done. just turned 80k but this has been going on for at least two years now. it does it summer or winter when you first start the truck up it jumps to app. 1200rpm and the drops really fast to about 600rpm and sometimes a little lower. and then jumps back up to about 1000rpm and then idles down. problem is sometimes it almost dies when it drops and now that its cold again it doesn't stay at high idle when you first start it in the morning or when i leave work in the afternoon. So far this summer i installed a new OEM IAC valve, throttle position sensor and fuel pressure regulator, and the rubber hose from the egr on the pass side fender to the back of the intake. i cleaned the mass air sensor dropped the tank this summer also and there was no sediment in thwere. i replace the fuel filter every 3k when i change the oil so i know its not that. i did a vacuum test and it all was normal. this is really getting old because my buddy has a 03 5.4 that he takes of road every weekend and it idles fine. r 2000 5.3 e-350 van had 130k when we traded it in on our new 09 e-350 5.4 van and both of them idle high and stay there for a while until it warms up. my brother 05 f-150 with 5.4 idles fine and stays there and then idles down normal. what could it be now since everything has been replaced??

 

another question what is the normal idle of a 5.4 in park and in gear? ill go start my truck and c where mine's at and post them

 

OK, it sounds like your truck has "learned" an odd idle pattern.

I would try disconnecting the battery, turn on the lights, wait a while for all they stray voltage to get out of the PCM and clear any of the idle code the truck has learned. Then reconnect the battery and start the truck up. Let it idle without touching the throttle for at least 5 minutes, then shut it down, restart it and drive it normal for a short trip.

 

i assume i should put the stock tune back in first correct?

 

No, I'd leave it as is and try to let the engine re-learn it's idle first.

 

ok thanks alot ill try it out right now