HELP 535is

Not too long ago, i was driving along and my 1987 535is engine started to pull instead of push. The engine refused to generate power and i barely made it to a parking lot. I could not find a tow truck that was able to tow it, because it rides too low, so i went over there (it was 36 degrees) with my tools and replaced the distributor cap, rotor, and coil, thinking that i had blown one of the three. All three were in very bad condition, and were ready to be replaced, but the car still had the same symptoms. The symptoms are: The car starts fine, and idles ok for a minute or so, then it idles at 500rpm and very rough. THe engine will sort of rev, but it will not give constant power. If I give the gas pressure, the rpm's will rise, then fall, and the engine will die. I thought that it might be a clogged fuel filter, but that didn't help when i replaced it. Both fuel pumps are working. I decided to test the fuelk pressure regulator, by squeezing the return line to build pressure and the engine ran properly!! i replaced the fuel pressure regulator and the car still had the same problem. I am absolutely stumped. Any advice on what to try next?

Did you find out what caused this??????.

The fuel pump, filter and regulator have been replaced with no results. This last weekend I replaced the MAF meter and the ICV. I was able to get the car to run again.

Symptoms. It will start cold and run perfectly with a smooth idle. As soon as it warms up the idle gets irratic and lumpy.

The other odd thing I notice is when I pull the throttle and hold it, the RPM's drop off and while holding it still they'll come back up. It acts like a fuel problem.

I would appreciate any advice..

Thanks

yeah, i figured it out. The problem was, that i had cut the wires to my oxygen sensor to bring the exhaust down, and when i reconnected it, i just used regular electrical connectors. Water then entered the connectors, and short circuited my sensor. I had a HECK of a time figuring it out. I ended up just wrapping the wires very tight in electral tape individually in the mean time while i wait for a new sensor to arrive. This sympton could also be caused by a broken oxygen sensor, so that would be a very valid thing to check. good luck

Thanks very much for the reply... I have the O2 sensor on order.