Idle speed too low

[Cheapo]

My festiva is idling way too low(200 rpm according to the tach) Any ideas why its doing this? I know a vacuum leak can cause a high idle, but not sure what causes a low idle

[htchbck]

Sounds like your tach may be off, have you tried verifying with an external tach of some sort? 200 RPMs is barely enough to keep the engine running, it would die a LOT if it was really at 200. Is this an EFI or carbed car? And other than the idle does it run ok when you are driving it?

[stonemaster]

does this happen when anything else is running ??? mine drop when the lights are on or if something else (AC) is going, but not that low

[WmWatt]

On a carburetted model turning the idle adjusment screw can make it idle too slow.

[htchbck]

Same thing with an EFI... plus there are other different variables that can affect it depending on whether its EFI or carb.

[Cheapo]

Mine is a '90 EFI model. Haven't tried an external tach. It runs great except idle. It doesn't stall very often, but idle doesn't sound too healthy. It surges a bit. If i give it a tiny amount of throttle, it idles fine. I don't think the idle screw was tampered with. Maybe the IAC is somewhat blocked? I think the car was mostly city driven, so I'm thinking the engine has some carbon buildup.

[Ogrestiva]

I notice that the idle can also change from season to season(i.e. summer lower idle/winter higher). so If it was last set in the winter (cold here in Illinois) it may need to be adjusted again.

[stonemaster]

Mine is a '90 EFI model. Haven't tried an external tach. It runs great except idle. It doesn't stall very often, but idle doesn't sound too healthy. It surges a bit. If i give it a tiny amount of throttle, it idles fine. I don't think the idle screw was tampered with. Maybe the IAC is somewhat blocked? I think the car was mostly city driven, so I'm thinking the engine has some carbon buildup.

same with mine, bump it and it idles better, and weather condition affect it as well, someone once mentioned o2 sensor could affect this,