Idle gone crazy!

It runs fine when cold, after it warms up when I'm at a stop sign or a red light the idle goes way down and almost stalls. Driving it is fine, as long as I'm on the gas. No CEL yet. IAC is only a couple months old, DPFE is only a couple months old, TPS is about a year old ang I cleaned the MAS a couple months ago also. Any suggestions?

vacuum leak?

It just started this last night. I'll try to check when it warms up a bit. With propane?

TTT

I saw that you changed the IAC, but when mine started to fail it always happened when trying to restart after the engine was warm, never when cold. Mine was sticking because I could see the spot on the shaft where it was rubbing when I took it off to replace it with another one.

You could check to see if yours might be doing the same thing. After you remove it, look for any evidence (like a shinier spot) along the shaft inside the two air openings.

CEL came on today so I stoped at AutoZone. P0171 and P0174. Guy said prolly O2 sensors but I'm not buying it.

Originally posted by checkedout
CEL came on today so I stoped at AutoZone. P0171 and P0174. Guy said prolly O2 sensors but I'm not buying it.

Click to expand...

P0171- System too Lean (Bank 1)

P0174- System too Lean (Bank 2)

Maybe this helps?

I did a search and it has been a common problem for the guys with the SOHC's it has been the lower intake manifold gaskets but the guys with the pushrods (like me) never posted how they fixed it.

Like I said, vacuum leak

Here's what my Ford CD says about PO171 and PO174. Note that one of the possible causes is a vacuum leak

pg 2

pg 3

Thanks, It looks like it's not going to be easy to find. I may have to bite it and bring it in to ford.

I would try the propane trick around the intake manifold first to see if you can locate it. If youre lucky, it could be something relatively easy like the injector o-rings or the IAC gasket.

I don't know about you, but my labor rates are much cheaper than the dealer

Yeah, but I tried the propane and found nothing. I don't know what else to try.

Stopped by ford yesterday and talked to the service guy. He said it's prolly the lower intake gaskets and if I want to bring it in I need to wait for the CEL to come back on (autozone reset it) What's up with that? So I asked him if that was the case it should be 'covered' since they just replaced my heads less than two months ago. He said maybe maybe not, depends on whether or not the replaced the gaskets which he said they don't have too they can re use them. But if that's the case I think I'll argue that they were not torqued right.

I tried another bottle of propane last night. Froze my butt off and still couldn't find any vacuum leaks

Why the hell would you try to reuse the intake manifold gaskets?!!!! You spend hundreds of $$$ in labor to remove the heads, and they cheap out by not replacing the intake manifold gaskets???

I think this guy at the dealer is blowing smoke up your a$$.

Thank you, I think so too. No way in hell I'm paying for that if that's what it turns out to be!

Hopefully it's not related but on the way home my doors locked by themselves and I couldn't unlock them then a few minutes later the hatch lock kept trying to lock click click click click then they all started to try and lock continuously! I had to pull over and disconnect the battery.

Your truck has been possessed by Satan.












Either that or you have a bad ground connection somewhere, but I'm going to stick with the Satan theory for now