Idle Increases With Temp

[BizarroStormy]

On 10/29/2020 at 8:17 PM, cruiser54 said:

For now........

 

Epic foreshadowing! Figured I would follow up on this thread because the previous fix didn't completely resolve the issue and I wanted to document the final fix.

The issue came back up after the engine got up to temp and I drove it a bit, the bolts kept getting loose.

So I pulled off the manifolds, cleaned the intake and painted the exhaust, new gasket and bolts.

But the idle issue manifested again this time after the engine would get up to temp then on second startup after it was warm would ramp up to 3k rpm.

Ruled out a manifold leak by blocking off my throttle body, then determined the IAC valve was wide open by covering it with my thumb and the idle dropped to normal.

Got a NOS IAC from eaglescout526 but that also didn't resolve the issue so I knew it was electrical.

I had already cleaned my C101 connector but it was still very nasty so I decided to delete it as documented on Cruiser54's website.

After deleting the connector the truck runs great, even after it gets up to temp and is restarted.

Thanks for all the help and Cruiser54 for his great information.

[BizarroStormy]

So I have still been dealing with this issue semi randomly and I have finally found the true cause. I replaced the throttle position sensor with a cheap one off Amazon a while ago trying to fix my issue. I noticed a few days ago when trying to diagnose the idle issue that the sensor was stuck. Turns out I had it too tight and it melted a little. So when the throttle body would heat up it would expand and make contact with the bolt on the sensors arm and bind it up. I pulled the arm back into the closed position and my idle immediately dropped to normal. I have since replaced it with a standard motor products one and it has been running great ever since.