I'm Back and my Maxima is still ...

[Dansmaxima]

I made an appointment with yet another garage that came recommended. My previous posts all asked about my 2001 se idle problems. I have had the car: SEC light come on every 200 miles with a catalyst code; recently it just stalled; then idled erraticly, surged. I replaced: IACV valve, all O2 sensors, MAFS, and now the TPS. Now the car wants to IDLE at 2900 RPM. Something is telling the IACV to go wide open. If I really turn the TPS out of whack the idle comes down to 1300 rpm. I did this to get it to the garage without having to tow it. QUESTION: Where is the PCV Valve??!! I have the factory manual on cd, it gives an indication of the location. I see the hose on the passenger side that connects the valve covers, and a hose connected to intake vacuum that goes into the engine near the throttle body. Is the pcv valve buried under the intake manifold in the back? I want to check it out or replace it. I WANT TO CHECK IT OUT BEFORE I TAKE IT IN TO THIS NEXT GARAGE. Tired of getting ripped off and having the problem not solved.

[Dansmaxima]

Also: I have a scanner that can clear the codes. If I disconnect any of these sensors, say the mafs, the sec light comes on with that code as it is supposed to. Sometimes I disconnect the mafs and the engine stalls, or the tps and the rpm changes, or disconnect the O2 connectors. Sometimes this lights the SEC light and pulls a code, sometimes it doesn't light the light! COULD MY COMPUTER BE SHOT? I found a place in Florida called http://www.ecudirect.com that wants $400.00 up front to Rebuild my own ECU or $600 to replace it. I'm a little suspicious since all I have to go on is a slick website. Also a mechanic told me that the dealer has to reset the ecu if it is replaced. Local dealers are all con artists around here.Thanks for any advice, I know I'm on a wild goose chase. Trying not to get ripped off is all... I don't mind paying, just want to find honest repairs.