I have a 98 Lumina LS 3.1 whose harmonic balancer fell apart yesterday. I stopped immediately when it happened. Today I installed a new harmonic balancer and now its throwing a P0303 misfire on cylinder 3 and it has to be cranked twice to start. I know one of the crankshaft position sensors are located behind the balancer. Could the harmonic balancer falling apart possibly damage that sensor causing my starting issues and misfire?

Thanks

 

Did the sensor look damaged? It could be possible that it is your problem however generally a crank sensor would not cause a single cylinder misfire.

 

The sensor did not look damaged, although it was completely covered in grease on both sides.

 

That is the 24X cps, it isn't into play until over 2K rpm (why chevy uses two cps, is well, more parts to sell you). You might clean it, and the refluctor ring, it looks like a hampster cage, make sure the balancer didn't damage it also. Misfire I'd replace the coil pack, cheap, easy, and probably the problem.