The car had a few symptoms.

- Stalls if not pressing the gas pedal while parked
- When after cleaning the throttle body, it stays running now, no longer stalls, but idles strangely idling higher than normal then lowering to normal. Even when the throttle body is closed, idles high

I replaced the IAC valve (Idle air controller valve) but no help. Air cleaner is clean. But i do hear what sounds like a massive air leak in the plenum air inlet manifold behind near the throttle body. Is this normal? Could a leak (crack) cause this idle issue?

 

Year and mileage please

I suspect you have a vacuum leak. One item to check is the vacuum line to the master brake cylinder. It will disconnect relatively easily. Other than that there are other lines coming off of the throttle body and intake plenum that may have been dislodged. You should also check the pcv hose as it may have split. You should not be hearing an air leak

 

2001 PT Cruiser Limited Edition

 

Take a piece of tubing 2-3' long. Hold one end close to your ear and poke around near all the vacuum hoses and fittings with the other end. If you hear a hissing noise near something, there's the leak. Good luck.

 

I found this image on EBAY of what the back of my engine looks like. I found a massive leak in what is perhaps a seal or gasket that is possibly mounted in this fitting juncture. (See image)



While the engine is running, you can hear the massive leak and place your fingers back behind the engine at this connection and feel the leak. Could this be causing my erratic idle control?

 

Yes, there is a blue seal/gasket behind the plate called the egr tube seal. The bolt sizes are 8mm and 13mm. The difficult part is pulling the tube far enough out to replace the seal, at least 1/2 inch.

Yes, if it a massive air leak as you describe it will cause an erratic idle. You may have located the problem. As a note it is necessary to remove the plate when replacing the spark plugs as the intake plenum needs to be moved out of the way to get to the plugs.

 

Thank you ggoose!!

 

Installing the new seal at this fitting fixed the idle problem as you suspected. Thanks for your insight!!