engine light at idle when outside temp >100F

[e34black530i]

In the last couple of months it has gotten a little warm here in Las Vegas. Last week we were around 115F. About a month ago the temp was about 104 and my little 3L V8 did some funny things after riding on freeway for about 45 minutes.

I pulled into the parking lot and before I turned off the car the engine light came off and the idle got unsteady. I turned off the car and removed the key, however, the motor continued to diesel for about 60 to 90 seconds. I just sat there with the tran in neutral and my foot on the brake, waiting for the motor to stop. I was worried and I immediately attempted to start the car after the dieseling quit, wouldn't start. The check engine light was on and the pedal test revealed Lambda sensor.

I went in the store for 30 minutes, grabbed my stuff and ran back out to attempt to start the car. Hoping that a cool off for 30 minutes would let me restart it. Not so lucky, car still would not start, and I continued to get the one error. I had to wait nearly two hours before the motor would start.

When I drove it home the check engine light would go away whenever I was moving, but as soon as I was stopped and idling the check engine light would come on and the idle would get very rough.

Since that day, I cannot drive the car longer than 10 minutes without the check engine light coming on at every stop and the idle going bad. And if I have driven the car for longer than 30 minutes straight and I turn it off, it takes about 2 hours of cooling/waiting before the engine will start up. Any thoughts would be appreciated.

The car is 5spd manual, 530i baby V8, 2000 miles on new clutch, O2 sensors replaced about 8 months ago, 123k on the car. Had the intake manifold gaskets and computer replaced at 70k miles. I hope someone has some simple answers Thanks in advance,

Robert

[Espen]

Have you checked the lambda? maybe its busted, so that it will throw an error code as soon as it gets warmed up?

[e34black530i]

I might as well climb under the car and have a look, sounds so obvious I didn't even think of it. I have her stowed in the garage, I'll check her out tonight when I get home. Thanks.