91 SE - stalling, no power - RESOLVED!

FInally (I hope) my problem is resolved.

First, 91 SE, manual transmission, 230K km. The car would suddenly have no power while driving. Later, I narrowed it down to a (usually) warm engine, pushing hard with a load (like running up a hill), and when letting the rpms drop to between 1500 and 3000. It would sometimes idle roughly. If I stopped and waited about 5 minutes, the engine would 'catch it's breath' and I could run it all day without problems.

Checked: EGR, no effect. Had Nissan dealer check computer codes - he said there were none, and was convinced that the problem was MAF. I cleaned up connections to MAF with contact cleaner and toothbrush, cleaned up ground connection to engine block, fixed a loose vaccum hose connection - no effect.

Checked computer - had code 33 (!). Followed Haynes manual instructions, disconnected the O2 sensor (what a pain in the arm that was!), and the car ran fine. Reconnected, the car ran like a pig.

Took it to Nissan - the checked out the O2 sensor, and replaced it. The car is great again!

Thanks to everyone here (and other boards) that helped me understand and resolve the problem.

Michael

RyderMax,

What did you use to capture the codes? Did the code 33 come after the engine died or during driving?

My symptoms are very similar to yours. Except, Texas has no hills. My hesitations also occur when driving steady in a low rev and then step on the gas for acceleration.