Need Help! Please Give Your Insight On Motor Issue!

[JBsZ06]

I've been experiencing some weird drivability characteristics...and keep thinking I resolved the issue.

The tech II shows no issue...and sometimes the car runs good and sometimes it runs like crap..

Had the car tuned by 4 times and the tuner says its not in the tune but rather something else..(not the vette drs by the way)

Anyways here's the story and maybe you can help...

The car holds the tune for about a week and then drivability starts to degrade...

so last night I disconnected the battery and said lets see if that does..

So I reattach the battery and start the car this morning in the garage...(outside is raining big time) Don't know if its part of the issue.

The engine starts and revs up and settles at 2,000 rpms...then 3000 rpms...

I drive the car out of the garage and the cars driving good...but when I depress the clutch the engine continues to rev to 2,000 or 3,000 rpms..

Once the engine warms up to normal operating temperature the pcm kicks into closed loop and the idle returns to normal 900 rpms..

So my question is:

Assuming the computer has been in the past adjusting for some "ISSUE" what is that issue? Remember I disconnected the battery overnight to clean up old history and start fresh...

Where would you look?

1)Would the issue be a throttle positioning sensor?

2)or the motor on the throttle body? How about a leak of air around throttle body?

3) intake manifold leak?

4) bad maf?

5) coolant temperature sensor is bad?

6) Injectors have gone bad?

7) bad fuel regulator/fuel filter?

8) Map sensor?(how to fix?)

9) head gasket leak? (coolant looks fine)

Tech II shows nothing wrong.

The tune works great as long as I reset it everyweek. During the week long of a tune something mechanical is causing the car to go "off tune"

This mornings experience leads me believe its a sensor or a air leak or fuel leak ?

What do you guys think?

What makes the idle go up to 2,000 or 3000 rpm steady at cold start up with no gas pedal action and stay there until the car warms up and goes closed loop (with computer readusting to bring the idle down) .... on a car removing the pcm tune from the equation?[/

[Speedratchet]

Did the problem start after any work or mods and you're not getting any codes?

[JBsZ06]

The idle raising to 2000 to 3000 rpms at cold startup? Thats a new thing since I disconnected the battery last night...

When the car warms up..it idles like it always does at 900 rpms..

No codes before or after disconnecting battery last night.

I'm really trying to figure out what simply would cause the idle to jump that high and stay there when cold..(assuming its not a tuning issue)

Could it be a bad maf?

A bad sensor or a bad gasket?

I realize the computer will eventually stablize the cold idle back down as it learns what it needs to do..

I just thought it insightful that this was occuring before the pcm can react and correct..

What might be the cause of an engine to rev that high at cold idle?

Air leak at the Throttle body? Gasket or o ring?

TPS bad?

Thanks for any guesses. ( did have a crushed air bridge that was allowing unmetered air into the throttle body but I have since fixed that issue by replacing with a stock air bridge) I had a pcv valve that was shot and replaced that too. Swapped in new rubber hoses to and out the pcv vavle as well..(was causing an issue I believe but thats been fixed too...)

I'm just shooting the breeze.

JB

[TheRobSJ]

So the TechII is showing closed throttle voltage from the TPS but it's taching at 3 grand?

I'd pull the air bridge off and see if the throttle plate really is closed when it says so.