Idle problem again

[mr_man]

about a month ago i was having high idle issues, but i replaced the IAC valve and everything was good. Two weeks ago the clutch in my torque converter got fried so i had to get a new torque converter(not sure if it has any relevance).The day after it got fixed i swapped vehicles with my mom to go on a trip (her vehicle has more room)and i get back today and start my car and it starts idling at about 1500 which is about normal when it's cold, then after about 10 seconds it slowly increased until it was at about 2100 and held there. My mom said this started yesterday, so it was running fine for about a week. After driving the car then putting it in park it idles at about a constant 1500. Any thoughts, or am i going to have to take it to a mechanic to find out what's wron?

[hockeyman]

I also replaced the IAC on my 3.8, and about a year later I had another idle issue. I took some things apart and found that there was alot of carbon build-up inside the intake right at/around the butterfly. Ultimately making the butterfly stick open just a tad enough to make the engine rev higher. I cleaned the whole inside of the intake bore and disassembled the butterfly and springs and cleaned them too. Re-installed it, and everything was nice again. If you don't want to tackle this kind of project yourself, see if you can get a reliable mechanich to check it for you. You may not need a cleaning in there, but then again, you may...

Good luck,
Marc