Weird Idle Problem

[Pete]

I do not drive the MX-3 very much, bought it for my kids. Had to replace the rear hub today and took it for a test drive afterwards and when I coasted to a light (stepped on the clutch) the idle went up to about 1500 RPM back down to 700 back up an so on. When I stepped on the brake it settled down. When I took my foot off the brake it went up again, but only to about 900. Every time I stepped in the brake the RPM seemed to go down a few hundred RPM. It was never in danger of stalling, but it is odd. Any suggestions?<P>Pete

[fieval79]

Mine is doing the exact same thing!!! <P>I've got no idea what it is.....but I'm going to try some different things out tomorrow, maybe it will help. When I do it, and something works, I'll let you know.<P>On another note, I've gotten a crap load of races because of the engine doing that......sounds like I'm revvin at a light

[OsoSlo z28]

check your idle air control valve. that's what was wrong with my altima. hope this helps.

[DVH]

yo guys ~!<P>i jusat want a header ! commmoooooonn!giuya!.........i m soooooooooooo drunk sorry for the gay asss resp0omnes! heheh! later boys keep on drinknin.......i'll try bnot and driv emy MX-3 !@ hehehheh........opps . m gettin a--!

[Pete]

Thanks for the responses. I have cleaned (?) the idle air control valve, but, just by spraying it out. There did not seem to be any dirt come out of it. I have also cleaned the throttle and butterfly. I did not remove them from the car, just sprayed in some throttle body cleaner and wiped out what I could.<BR>Any other suggestions?<P>Thanks <P>Pete

[OsoSlo z28]

do you have a multi meter? if so, check the voltage on it. sometimes the actual solenoid goes bad. i don't know what the actual readings on this car should be. check the online manual...maybe it's in there.

[fuzzpimp]

My car does that too, but it didn't start happening till I advanced the ignition timing as far as it would go, you could check that

[bslenderpeak]

This is a quite popular thing to have happen on these engines. If the spray cleaner doesn't work you can have a shop replace the little gasket between the throttle plate and the Idle air controller (although they probably get a good chunk of change when you can do it yourself). It's my understanding that one of three things could be happening: The valve is infact just dirty, the gasket dried up and is creating a vacuum leak(the RPM fluctuation is normally a vacuum leak), or the valve has failed and needs replacing. If you are handy with cars I would test the valve as mentioned with a multi-meter and if it checks out, replace the rubber gasket between the throttle body and IAC valve which requires taking the throttle body off of the intake manifold to gain access (then you have to replace that gasket too) while you have it apart clean the valve and the valve body up thuroughly with a fuel injection safe cleaner spray of some kind(this will ensure that you don't damage the IAC valve, some chemicals out there would just eat it right up). You'll have to reset your Idle screw when your done. You can find the pictures for all of this in the online shop manual. I feel I'm going to have to do this with mine soon let us know what you end up doing and how it works good luck.