when the car is warmed up it sometimes idles at about 600 but sometimes bout 1400.. got a eg coupe with a ls swap any solutions

 

Don't want to sound mean but did you search?
=o

Check your Idle Air Control Valve (IACV), Fast Idle Valve(FITV), or it may be a vacuum leak.

Might I add...Invest $20 in a Helms or Haynes Repair Manual. Lots of DIYs.

 

By the way...if your car is a '96+ you won't have a FITV.

Correct me if I'm wrong.