idle surge problems

[zerokool]

So I've developed an idle surge problem. It will happen both while coming to a stop and sitting with the truck park idling, randomly. While sitting, the idle will drop enough for it to almost die, then pick back up. This doesn't happen all the time, and I'm not having any issues while moving. Cruising down the road, it runs perfect. I've read through some threads and found that it could either be a failing fuel pump, fuel pressure regulator, pcv valve or hose, or tps sensor. I'm not getting a check engine light. I'm 03 cable driven throttle body. Anyone have this problem and solved it? I know I can test the fuel pressure and have seen some info on testing the tps, but if anyone had this problem before that could point me in the exact direction, it would save me the time I don't really have to diagnose it.

 

[zerokool]

it's a lot like this guy's explorer, except i'm 4th gen
http://www.youtube.com/watch?v=A9uSBtNvKB0

 

[wesalexleft]

Idle surge

Same problem here. Very infrequent, and happens as I'm coming to a stop. It's a real pain as you're coming to a stop at an intersection and just as you think you've stopped, it surges and wants to put you in the intersection. Happens to me maybe once or twice a month tops. Might be just me, but seems it happens at a weather change, like a rainy day. I haven't looked into it too deeply yet though. No CEL for me either.

 

[zerokool]

I noticed I was having problem with the weather change too. I was also getting cel p0174 and replaced my intake manifold gaskets. The light is gone. I had this problem prior. It ran perfect for about a week then started acting up. I didn't see any issues with hoses except one that ran all the way across the engine bay that i replaced.

 

[blownmarauder]

clean or replace your IAC (idle air control motor) mounted on your throttle body

 

[zerokool]

thanks for the direction blown. I'll give it a shot and see how it pans out

 

[wesalexleft]

Solved

IAC valve did the trick. Not cheap from the dealer for the factory valve, bit the fix took 10 minutes, so I'm happy. Looks like I could have just cleaned the valve, but I'd already made the buy. Still, problem solved.

 

[tmaher]

0171 and 0174 (lean conditions banks 1 and 2) are common codes for the elbow shaped hose that goes tothe PCV valve for the 4.6L. The hose is located in the center of the engine. vacuum leak is the cause of the codes. changing intake manifold gaskets didnt hurt but i bet that hose has a break in it. very common problem. get a generic elbow hose and cut to length and install. this will fix this problem.

 

[swshawaii]

http://www.explorerforum.com/forums/showthread.php?t=217062