92 F150 302. So I was having some idle surge and poor drivability recently. The check engine light was on and codes read an egr code, tps, and something else (done at a shop). So I also found a vacuum leak leading from the coffee can which I guess can cause the egr code? I just spliced it with a piece of rubber hose to see what I would get, so keep that in mind. Then even though my uncle (mechanic) replaced my tps, the shop said it was bad. So I put a new tps on and while I was at it I cleaned the throttle bores out pretty good. So as of the past couple days of driving, no check engine light and no "original" idle surge. However when I am driving and shift gears the rpms will spike to 2600-3000 rpms and then slowly come down but only to about 1100 rpms. If I sit in neutral the truck will eventually come down to about 800-900 I guess. So any ideas on fixing this? Could it be the half-a** vacuum line fix?

 

IIRC, pull the negative cable for 20 minutes then hook it back up. This will cause the computer to have to relearn the settings with the "new" parts.

Hopefully it is something as simple as this.

 

Did you clean the IAC valve? That's the most common cause of unstable idle speed.

 

Sorry for getting back so late. I cleaned the iac when I put on tps. I will disconnect battery over night. When I start it back up do I have to do the throttle at 2000 rpms for 2 minutes ac on and ac off?

 

Drive the truck like normal. There is no reason to do much of anything special.