IAC Valve Maintenance, Symptom was Seemingly a Starvation of Fuel

[Blue Flame Restorations]

Solved an issue today.

Started the car this morning and after about 15-30 seconds the idle began to rise to over 3k. I blipped the throttle and it did not come back down.

Background Info

My car ran very inconsistently shortly before Bowling Green in May and after I got home, a fuel pump failed. I installed CHEAP Airtx fuel pumps (I had them, so I used them)

When I would first drive the car in the morning, I'd get a stumble from 1st to 2nd gear when pulling out of the neighborhood. Yesterday, it almost died due to starving of fuel. After warming up, it runs OK but feels like it's starving for fuel, to an extent. I thought maybe one of the cheap fuel pumps was beginning to fail?

Today

After my high idle occurred, I checked the MAP hose and also the IAC connections. TPS was not loose. Shut off car and re-started. Idle was ok. Drove car and it still felt like it had a weak fuel condition from the pumps.

I loosened the IAC valve and began to clean it with solvent. Wahla! A large chunk of carbon fell out onto my hand. The chunk was about 1/4" or larger and it was also thick. I finished cleaning the IAC and the spring and also the hole in the plenum. Re-attached the IAC and started the car. Seemed to idle just fine. (be careful not to drop a screw underneath the plenum)

Drove the car. Exhaust note was nice and smooth and no more stumble.
Ripped a few gears and PERMAGRIN is back!

My Point

I'm slowly learninig the preventive maintenance of the LT5. It's a lot of enjoyment when you start to get the feel of the car and know how to diagnose issues as they come up.

Maybe this post will help someone inn the future???

Brett