Hey guys, I noticed with my truck (02 F150 5.4) that after driving for awhile and its warmed up, when I stop somewhere, as soon as I put my truck into park. the idle will fluctuate from idle to almost stalling, but then eventually even itself out (after about 10 seconds)

does anyone know what could be the problem? my truck isn't throwing any codes.

 

Does it do it at stoplights/stop signs while in the tranny is in drive as well? Sounds like the IAC (Idle Air Control Valve), that's exactly what happened to mine when the engine RPM's would drop, as such when stopping, the engine would shutter for a couple of seconds, up and down, then smooth out. Only happened everynow and then, mine didn't throw a code until it got worse, which it will. You can try cleaning it, but once the carbon gets built up in it, it's hard to get it all out. Might as well get a new one, they're not that expensive.

 

Oh by the way, I don't know if this is the same with the 5.4 engine, but I had to buy an IAC for a 2001 F150 4.6, to match my truck whick is a 2002. When I ordered the part for a 2002, it was a completely different design, which apparently had been changed mid year of production. But like I said, the 5.4 could be different. It's simpe to remove, (3 bolts) you can remove it at the auto parts store parking lot, just to make sure you have the right one. Funny thing though, the 2002 IAC I originally ordered was around $75 bucks, but the 2001 was $35, so my truck saved me $40.

 

well, it doesn't do it in drive, only when I place it into park. I'll try pulling off the IAC and give it a little cleaning and see if that changes anything.