Rep Power: 0

alright so look in my sig for what my car is... when the car is cold and plugged in(block heater) i can start it and hold the rpms anywhere between a bit above idle to 4000 rps and its souning like its hitting the rev limiter but i know it isn't because i can go to a different rpm and it does the same... BUT once the car is at temp and i shut it off turn it back on problem is gone??? WTF! i mean its not really serious if it goes away... but its annoying

 
Rep Power: 285

Takes some time for the engine to reach operating temperature and perform to the optimum conditions, even with a block heater.

 
Rep Power: 0

i know but this odd reving? i know for a fact that is should not do that..

 
Rep Power: 285

If the rev's are jumping up and down while its cold at idle there could be a few problems, most can be addressed through basic maintenance.

Change the spark plugs, change the O2 sensor, clean out carbon build up in the IAC valve and throttle body, dump in a bottle of fuel injector cleaner. I know you can't change the spark plugs..