I am getting an intermittent Check Engine light with a code "8" which is a TDC position sensor problem. The car is difficult to start sometimes which is when it throws this code. When the engine cranks but doesn't fire there is a spark as seen by using a timing strobe. When it does start back up the Check Engine light disappears.

Does anyone know if it is possible for the TDC sensor to fail intermittently yet still get a spark out of the distributor when the TDC sensor is in the failed state?

 

It's possible the inside of the distributor is either dirty or you have the red dust of death setting in from internal bearing failure. You could spray out the inside of the distributor real good with electrical cleaner. If red dust is inside just replace it.

 

Thanks for the suggestion. I took apart the entire distributor last night and cleaned everything with electronic cleaner. No red dust. Bearings were smooth. I tested the resistance on each of the 3 sensors. Each of them were at 880 ohms (within spec). I put it back together and reinstalled. Ugh... Still the same problem intermittently by not firing when I let the car sit for awhile and then go to start it. When it did start I adjusted the timing. But is still has starting problems when I let is sit for awhile. It still throws the "8" Check Engine code (TDC position sensor problem) periodically too. Then it goes away. This is beginning to smell like an intermittent electronic circuit problem in the distributor or in the main computer.

I'm open to other suggestions...

 

I had a friend that had the same issues you are having, especially when it was wet and rainy outside. Replaced the distributor and the issue went away.