02 Monte SS, 167,000 miles, New ECM, New MAP sensor, Ignition Module, CSV and TPS. No Codes. No loss of power.

Help me guys, I can't get the car to Idle right. When the engine is cold, it will rev all the way up to 2300 rpm. When I'm driving, if I take my foot offthe gas at 1500 rpms, it stays at 1500. Or 2300 or whatever rpms it happens to be at when I take my foot off the gas. When I come to a stop it will come down to 950 to 1200 rpms. If I put it in neutral the rpms jump to 1800 and then back down to 1500. And the problem doesn't show itself all time. Just most of the time. Now, I changed the air filter and the problem vanished for a day. Then came back in the morning. It seems like every time I mess with the air filter or in that area of the intake, the problem goes away till I Cold start. I change the CSV. Same results. I spayed the Throttle Body with cleaner. Same results. The thing that is really stumping me is that there are no codes. I've had it checked twice. I'm sad and frustrated! 30+ years under the Hood of one car or another. This one is throughing me in a loop!
I love my Monte unconditionally, but she's not returning the love! Please help! PLEASE!

 

I would check your Idle Air Control Valve..

 

Idle air control valve, throttle position sensor, coolant temp sensor,

 

I change the TPS. Is the IAC (idle air contr valve) different from the CSV (cold start valve) and wouldn't either of them cause a code to come up?

 

I'm thinkinig Mass Air Flow sensor. Get the MAF cleaner from the parts store, follow directions on the can and see if thei yields results.

Also, check for vacuum leaks. Easy way to check is use a can of starting fluid and mist it around all vacuum lines and connections, see if the idle changes.

Other items to consider:
- Do you have a check engine light, if so, what's the code?
- Change the upstream O2 sensor
- Change plugs and wires (assuming they are worn out and not giving good spark, if they are BOSCH plugs, ditch'em now).

Just a couple of thoughts.

 

These guys got the idea - check the IAC, TPS, and especially check for vacuum leaks.

 

did you check the Manifold Absolute Pressure Sensor (MAP)? Also check the Throttle Position Sensor (TPS) There is a gray wire, dark blue wire, and black wire going to it. Good luck!