My bonnie has a rough idle when it starts up. I thought it was the crank position sensor and i replaced it. no luck.
so after some more reading i think i could be the IAC valve... i figure id give cleaning it a try. but i have 2 questions
1. it only idles bad after the initial start up. after is been driven around it doesnt idle bad at stop lights or while in a parking lot. if the IAC was going bad/dirty wouldnt it always idle bad?
2. What should i use to clean it? I did a tune up and i used maf cleaner on the maf and throttle body cleaner on the TB. can i use brake cleaner on the IAC? Im just wondering cause i have a lot of brake clean and no maf or tb cleaner. i just dont want to hurt it you know?
IAC valve questions...
- Archon
- Resident Gearhead

- Posts: 8781
- Joined: Mon May 19, 2008 10:30 pm
- Year and Trim: 2014 Cadillac XTS Vsport.
- Location: Grand Rapids, Michigan
Re: IAC valve questions...
The IAC has more of an effect on the idle speed, than idle quality. I'd suggest sticking with throttle body cleaner to clean it. Clean the passages well, too.
Have plugs and wires been replaced recently?
Have plugs and wires been replaced recently?
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.
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mrrcom
- SLE Member

- Posts: 80
- Joined: Mon Jan 27, 2014 5:41 am
- Year and Trim: 2000 Bonneville SSEI
- Location: Rockford, IL
Re: IAC valve questions...
Update...
I used throttle body cleaner on the IAC... figured better play it safe. and IT worked! When you mention idle speed it was kinda idling slowly id say maybe around 550. I think its supposed to be around 800? Anywho I thought it was the crankshaft position sensor at first but that wasn't the issue.
When I got the car from my parents they were switched out around the 100K mile mark now its got 220K lol. I should probably change them.
When we had the trans out it seemed like the wires had been melted on! haha i didnt want to break anything so i said id change em at another time.
I used throttle body cleaner on the IAC... figured better play it safe. and IT worked! When you mention idle speed it was kinda idling slowly id say maybe around 550. I think its supposed to be around 800? Anywho I thought it was the crankshaft position sensor at first but that wasn't the issue.
When I got the car from my parents they were switched out around the 100K mile mark now its got 220K lol. I should probably change them.
When we had the trans out it seemed like the wires had been melted on! haha i didnt want to break anything so i said id change em at another time.
- Archon
- Resident Gearhead

- Posts: 8781
- Joined: Mon May 19, 2008 10:30 pm
- Year and Trim: 2014 Cadillac XTS Vsport.
- Location: Grand Rapids, Michigan
Re: IAC valve questions...
Happy to hear that you got it straightened out, and thanks for reporting back.
*Gone, but not forgotten* - Black 2000 SSEi, HIR Headlights, Angel Eyes fogs, 3rd brake light overlay, hi-flo cat, 180 degree thermostat, HS 1.9 rockers, LSx yellow springs, Intense FWI, PCM, shift kit, push rods, and 3.4 Pulley. ZZP Power Log.

