OK guys, this has been ongoing problem for a while now, I thought I had it fixed...but I guess not.......I know its LONG but please help.....

When my truck is at idle it often dips below the 500rpm mark as if its going dead. It never does but it just sounds like it. Also, If the truck is idling and you mash the gas....lets say 4000-5000rpm and let off....when the truck comes back to idle it does not hold at idle it dips below as if its going to go dead then comes back to idle. Also, this may or may not be a problem....If you give the truck gas and hold it at 2000 rpm its sounds like their is a miss....there is like a popping, if you go to higher rpms...it stops!

I have taken the truck to Ford for this problem, they searched for vacuum leaks....found nothing. They eventually changed the IAC and that seemed to fix the problem for a while (the idling problem). They said the miss or popping sound from 1500-2000rpms was the exhaust, (I have full exhaust, headers, ect). Then just a few days ago the truck starting making a horrible noise at low rpms, like a loud whistle...kinda like if you blow into the top of a Coke bottle, more like a howl. Took it back to Ford, the again changed the IAC...that fixed the howl but now its idling like crap again. DO you guys have any idea what this could be....PLEASE HELP!!! I am at my wits end with this problem and the truck and could be about to get rid of it if I can't get this problem fixed.

P.S.- The truck other than the problems listed runs great! It seems like a minor problem that I just cant find. I also changed fuel filter and PCV Valve.

 

Anything???

 

Try removing the maf and cleaning the little hot wire with a q tip and some solvent?

Maybe its a little dirty?

 

have u checked your plugs and fuel injectors.
Also, i think u might have mentioned this, i dont know what its called but i had a problem like this when this hose here was messed up cause it got burned by the hot metal pipe in the background.

 

I had the same problem on my L but it was 3 years ago so i had forgot. MIne caused a check engine light and a small surge but nothing like you say. MY truck does exactly like you say when i have my JDM chip in it. take it out and it goes back to normal. Just part of the tunning

 

I second the idea of cleaning the MAF wire, but not with a q tip. Break that wire and you're buying a new meter. Just spray brake cleaner on it and let it dry.

 

Thanks for the info guys...Any more suggestions??