Skyhawk

When i was out last night i pulled into park at this place and as i was sitting there i noticed the RPMs jumping back and forth from like 500-around 1300 quickly and the oil pressure would go down a considerable way everytime it did it. I also noticed that while i was driving that day the car was a lot slower than normal in the lower RPMs and then when it would get above say 3000 or so it would just jump and accelerate normaly. Could this be the spark plugs and wires or something? Does anyone know whats wrong with my car? My car has 110K on it if that helps.

Javelin3o4

are any othe gauges acting up? i had issues with my gauges and it turned out to be a broken engine to body ground.

Skyhawk

i thought about that but the engine is reving up also when it does it and then back down so its not that.

kahouna23

Does it do it more when it's cold or all the time? The RPM's fluctuating could be a reslut of a faulty IAT or MAF sensor, or getting ready to be faulty. In case you're not familiar with what those sensors, do, they read ambient air temp and send a signal to the ECU which regulates the air/fuel mixture. Resulting in a fluctuation in RPM's as it's regulating the mixture.

Your oil pressure gauge will fluctuate since your engine RPM's are fluxing. That is just one of those "chain reaction" deals that would be especially noticable at idle.


Then again, I could be TOTALLY wrong. If you have access to an OBDII scanner or know someone who does....hook it up and see how it's running. Have you noticed your gas milage going down the tubes considerably? If so, I'd say the above mentioned would be a good start. Doesn't sound like a spark plug/wire problem to me.

HBHRacing

if it's bouncing in between 500 and 1300 only at an idle 9 times out of 10 it;s the IAC gone bad. pull it out and see if it;s really dirty but chances are that it;s bad and needs to be replaced

Periculum

Ive had a similar problem in my camaro, but only when i put it in nuetral (manual). Rarely though, the RPMs will drop down to 500 (enough to almost kill the lights and such) and then pops back up to normal. I have also lost my power steering on two rare occasions under the same circumstances. either my P/s pump is going out and putting drag on the belt or the drop in RPMs is too low to run the pump efficiently. All this only happens in neutral.