My '85 244 runs now, but very badly. After cracking the throttle to rev it up, the idle drops low, almost dies, and hunts up and down like the engine is searching for correct timing. Not enough power to drive it.

I was checking electrical connections under the intake manifold today and pulled the wire off the knock sensor to clean it. Then I noticed that the plastic end of the knock sensor had broken off.



The metal part of the sensor was screwed into the block only finger tight. Maybe the knock sensor was broken internally before I pulled off the wiring harness connection? I hope that is the case if it could be the source of my trouble, because it would be an easy fix after much toil.

What do you think?

Rather unfortunately, the replacements I've found online are very expensive: Sensor from PartsGeek. Sensor from RockAuto.

And now for another ignorant question: Is this style of knock sensor common to any other cars of a certain vintage? If so, maybe it would be cheaper to get a replacement from the local O'Reiley's, I reckon. I called them asking for an aftermarket knock sensor for my Volvo. I was on hold a long time. Then the guys said said they would "have to make inquiries at corporate headquarters" and will call me back. I won't hold my breath on that.

Thanks in advance for advice.