Ok fellas, here's an update...

Last night I did some more poking around. I narrowed it down to what I believe was a bad TPS. After removing the connector the engine no longer idled high and the accelerator pedal was much more responsive. I did another thorough check for vac leaks and still couldn't find anything.

Today I picked up a new TPS and installed it. Once I had the TB off, I did what Steve and Bluegrass suggested. I looked at the throttle plate to see if it was fully closed...Nope, it sure wasn't, there was about a + 1/16" gap. I could see where some dipchit had taken some vicegrips and adjusted the set screw. I backed off the screw to bring the plate down to were I could barely see any light as well as make sure the plate wasn't going to stick.

I put everything back together and fired it up. I first went through the idle reset process with incremental loads. The thing still has the cold idle problem, but once it was warmed up it ran great and curb idle is around 650-700rpm.

I'll run it for a few more days to see if it adjusts itself after time (doubtful with the cold idle issue being so erratic though).

Now off to take the A/C.

Thanks for all your help!
-Ed

 

Ok, still SOL on the cold idle acting up.

When I first start the truck cold, it idles at around 400rpm and I can hear a whistling sound coming from somewhere. I can't locate it though and it's driving me nuts.

I read somewhere it could be a bad EGR valve. Should I just take the valve off and try to clean it (if that's possible).

-Ed

 

I'll bet it's that elbow behind the IAC - The 90 degree elbow stemming from the PCV valve that plug into the back of the manifold. Right after a cold start , reach back there - you'll feel it leaking and the whistle will change when you move it around a bit..

I think I have a pic of that..

Here yuh go - back against the firewall -

 

Welp, still screwed.

I started the truck cold and grabbed all around back behind the intake manifold and didn't feel any leaks nor did the whistling stop.

It kinda sounds like the whistling is coming from my air pump area, or close to the TB. I've sprayed and moved stuff around and nothing.

Once the engine is warm there's no more whistling. My air pump no longer blows air out the exhause port either. NO idea what that's about.

-Ed

 

I don't know what the air pump is - AC ? condensor ? blower motor ? Idonno what you talking about ?

The blower motor doesn't work ?

just guessing..

 

The air pump is part of the secondary air system (smog stuff).

Here's a drawing courtousy of Steve83.
http://www.supermotors.net/vehicles/...y/media/252396

The exhaust port shown here: https://www.f150online.com/forums/sh...d.php?t=288742
Is the thing that is no longer blowing out any air. It used to.

Thanks
-Ed

 

Sorry , I should have looked back , you talking about a 90 model - I'm not familiar with those.

It would help if you profiled your truck - then it would show up in the top right corner of each post - then theres no guessing or looking up - you might get more answeres that way - the right ones.

 

Good idea! Added profile and signature.

 

Might help if I check the Show Signature.