QuestionHi Tony,I have a 1986 325e bmw some days it drives good lots of power then for a day or so no power it seems to go back and fourth parts installed fuel pump in the tank and the one out on the frame mass air flow meter gas filter plugs.Does this sound like the TPS sensor or O2 sensor what do you think? Thank you JD
Answer ahhh, a 2.7 eta engine!
Haven't worked on 1 for a while.Terrible reputation for cracking cylinder heads, but that doesn't seem to be the problem here'
Scanning no good as its too early.
Simple answer to your questions is to unplug the throttle switch then the o2 sensor as you can run the car for a SHORT TIME, i a quick test drive to confirm.The throttle switch is not a potentiometer, simply closed throttle signal(idle) no signal mid range and full throttle signal. clean the contacts while unplugged.
o2 sensor wouldn't give you a significant power loss.
Fuel pressure possibly, check the vacuum hose to the regulator at both ends for splitting.Also inspect the large hose attached to the air flow meter for cracks.
It could be the rpm sensor or the reference sensor, located under the car plugging into the bell housing of the gearbox.
Take them out, clean the connectors and the crap on the magnet end.
The reference sensor "see's" a single pin on the flywheel, while its out look up the hole to verify its there, not broken off.Its the one further back, the other 1"reference sensor" is reading the flywheel teeth.
Good luck.
Tony
