Howdy folks, lookin for some insight here on what I think is either an intake or vaccum issue.
my '93 5.0 flareside isles unusually high. It's more subtle from a cold start but after warmin up and being in gear for a while, when put in park or neutral it revs very very high(no tach so I'm not sure the rpm.
I've cleaned the throttle body, replaced the iac, put in a new pcv valve and got a new air filter. I noticed that when I put in the pcv, the old one was on the hose hanging loose and not in plugged in. This all seemed to help a little, but it's still a big issue.
I have a new tps in the mail that I hope will fix it, if that doesn't work, I figured I would replace all the vaccum lines. I haven't noticed any leaks, but I imagine there's probably a lot of build up in them.
Any advice or ideas would be greatly appreciated, I need to get my emissions tested (for the last time) and the shop won't even take it inside

 

Sounds like you have replaced a lot of things. Have you tried resetting the computer so it can recalibrate itself?

 

The new tps is in and I reset the computer. It sounds like it still needs to self adjust a little bit, but it seems to have fixed the problem. Unfortunately, now that it's running at a lower rpm, the sound of a squeaky pulley is much more apparent. The hunt begins...

 

Honestly I've seen these problems quite a bit and the tps rarely fixes the issue. Hopefully it does for you though. Did you attempt to back probe your sensor to get a reading from your tps just to make sure that was the issue? And good luck with the squeak! Lol my guess is that your real issue was the pcv line being not properly connected. When put to idle the vacuum in the pcv line changes which if not hooked up properly would cause a high idle. My guess is the reset computer is just starting to recalibrate from that change

 

I didn't try testing the tps, I didn't want to risk frying the computer (electricity and I don't get along so much) and for $21 I don't mind having shiny new parts under the hood, even if they didn't need to be replaced. Whatever it was-I'm just glad it's fixed. Hopefully it will pass emissions now...assuming they let it in their shop with a rotten front suspension and no parking brake. Ha.