2000 Deville

CHERIE5295

MEMBER
2000 CADILLAC DEVILLE

2000 Caddillac Deville, 4.6L V8 engine, 102000.
Problem:

Started to stall at red light or stop light, and engine revving irratically. At times rev very high then very low, then irratic low to high, and coming to stop would make it stall.
Service Engine Light comes on, run the on board Diagnostic codes and get PCM P0101, P0171, P0174. New rebuilt Mass Air Flow sensor put in three times, returned several due to same problem. Fuel filter changes, air filter changed, put in new throttle sensor, checked EGR valve, not sticking, Put on new Catalytic converter, and all three O2 sensors replaced with brand new.

Car still comes up with PCM P0101, Mass air flow sensor problem, and the irratic revving and stalling continue.

Have exhausted all possible fixes that I know of.

One more code: C0663, Exhaust valve control circuit high. Could this be the problem and how can I fix it?

Thank you so much!
DESPERATE!

2 Replies

BASOD2002

MEMBER
4 POSTS

I've been having similar issues. I just replaced the idle air conrol valve (IAC) on mine and still have eratic idling. Inspecting for intake leaks especially around the silencer, apparently they can develop cracks. Another interesting thing I found on Borg-Warner website concerning IAC, is an issue with alternators failing. The only way to test is for presence of AC voltage for main output to chassis ground, I believe 2volts AC is indication of a voltage regulator failure. The PCM will sense a drop in voltage and cause the engine to rev erratically at low loads.

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Wednesday, July 4th, 2007 AT 4:10 PM

CHERIE5295

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4 POSTS

Thanks for the response! Much appreciated.

Update:

right after I post this info I drive the car to work. Same symptoms. Only this time when I park the car in the parking garage and turn the ignition off, I hear this bubbling, like water boiling. I look up at the dashboard and steam is coming out on the passenger side. I open the hood and look in, loads of antifreeze leaking and running down the garage floor.

So, end up having it towed home, my husband tears the engine down, cleans every thing, no leaks detected, puts a new temperature sensor in and PCR valve, and guess what he finds, a broken IAC valve.

Irratic revving has stopped since PCR valve installed. But accelerates by it self without exceleration. He checked the battery and alternator voltage, and all normal.

So. The pursuit continues. New IAC valve on order and hopefully it fixes.

Thanks again for your response.

If you have anymore suggestions, please let me know. Thanks again.

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Friday, July 6th, 2007 AT 6:26 AM