Bad IAC?

[LS2 KLR]

My car has been idling weird lately. When I come to a stop it will stay 1500-2k for a little while and then drop suddenly often causing my car to die if it doesn't catch it soon enough. Sometimes it even idles as high as 3k?

 

[Dark Knight GT]

A bad IAC typically does cause an odd and rough idle. Here's what I'de try. Go to the autoparts store and pick up two things. Carb and choke cleaner and along with a fuel system cleaner additive. Take the IAC off and clean it then when you fill up next time on gas, dump the fuel system cleaner in. This should help.

When was the last time you changed your spark plugs and when was the last time you changed your fuel filter ? I'm imagining with your setup having good plugs and a clean fuel/intake system is very crucial.

 

[LS2 KLR]

My plugs are brand new. I had a nitrous backfire recently and I'm thinking it messed up the IAC?

 

[Dark Knight GT]

Well, if you're firing nitrous and it backfired, you might have messed something up but I doubt the IAC. I think if you do the stuff I've suggested that would help. Also, have you gotten the SES light at all ? When was the last time you changed your front two o2 sensors ?

 

[danny g]

i had a similar problem and i tried cleaning the IAC. It did nothing. I dont think cleaning those things help. I say give cleaning a try (it wont cost you anything) and than go with a new iac from strauss or pep buys etc if it doesnt work. I would be surpised if cleaning it helps and I dont think those additives are goos for your car. I used a bottle of it once and it made my car run like poop. you are better of replacing the fuel filter every so often than buying the fuel system cleaner stuff. They should be about the same price anyways.

 

[Dark Knight GT]

i had a similar problem and i tried cleaning the IAC. It did nothing. I dont think cleaning those things help. I say give cleaning a try (it wont cost you anything) and than go with a new iac from strauss or pep buys etc if it doesnt work. I would be surpised if cleaning it helps and I dont think those additives are goos for your car. I used a bottle of it once and it made my car run like poop. you are better of replacing the fuel filter every so often than buying the fuel system cleaner stuff. They should be about the same price anyways.

Well, a lot of those fuel system cleaners depends on what kind you get. If you buy some crappy brand like STP or some off the wall brand, then yeah, it's not going to do much and it might very well make the car run like crap.

Now that I think about it, I'm wondering if his cars chip is custom tuned for the nitrous setup or not ?

 

[LS2 KLR]

I'll try to clean it first since a new IAC is over $60. I installed my new shortblock back in Feb and replaced alot of things as well. All of my o2 sensors are new as well as my injectors. My fuel filter was changed a few months before that and I of coarse only run 93 octane. My car has a flip chip so I have a tune for motor as well as nitrous. Currently I have no codes popping up

 

[Dan_Soprano]

either the IAC, Throttle Position Sensor, or a Vacuum leak.