The car has 152k on it. Plugs have probably 10k on them, wired 50k. The 02's have not been changed and I'm sure I'm losing some power there so I'll replacing them in the next week or so.

the problem

When at idle, the car after running for a few minutes wants to "surge" and by that I mean the RPM's fluctuate a good bit just above 500. The oil pressure drops and raises as the RPM's do. It almost has a "lope" to it and several people have asked me if the car is cammed. When the engine is cold and I start it theres no problem, it's just when the car is warm. Through the rest of the RPM's the car performs fine and doesn't skip a beat. Any ideas what the problem might be? I'm sure the description is a little vague but thats all I have. Thanks for looking.

 

Your IAC (idle air control) can be gummed up over time. I'd take your TB apart and clean it. Be careful with the AIC valve, it's fragile. I'd also install new O2 sensors...you're over due!

 

I would say your also over due for wires. But when your at it, go ahead and put some new NGK TR55s in. The O2s should be changed as well. If you do this I think it will prolly cure your problem.

 

i have the same problem.. the car will idle at 500.. it used to do it pretty rarely now it does it pretty frequently..

everyones told me its probably ignition system.. definately ANNOYING as hell.. especialyl considering my heatshield is loose, that 500rpm vibration shakes the hell out of it. But it doesnt really surge at all like you were saying.. Not sure how old all my ignition stuff is, but I've had the car from 104k to 135k and havent replaced it yet.. Going to get all that stuff done in the next month or so. Keep me up to date if you find a fix other than the ones mentioned (which I still need to try)

 

I had a very similar situation with a former car. It would be fine cold, but once it warmed up, it would start to surge, and got progressively worse over time.

As it turns out, a few fuel injectors were on their way out. Given the miles on your car, it wouldn't be a terrible idea to have those checked at the least.

 

my car did the same thing when the opti went out

so heres hoping for the iac

 

*raises hands and makes a cross out of index fingers*

 

I would replace the wires, plugs and clean the throttle body, including the IAC.