Pontiac Repair: 1997 Grand Prix tach jumping, car dies when engine heats up?, crank shaft, rodent damage

Question
My father in laws car starts fine but after running for a while the engine bogs down, the tach is reading 3500-4000 while at  idle. Recently, it started dying after being ran. Changed the 7x crankshaft and 24x crank sensor. Still doing it. Changed those per the autozone computer check. Any suggestions? Thanks for your time!

Answer
Hi Sarah:

I'll assume this has a 3100 V6 engine in it? If so then the other possablities are an ignition module or possably the wiring between 7x xensor and the ignition module I have seen the wires melt due to them being to close to the exhaust due to the retainer for the harness breaking. I have seen rodent damage to the wire harness as well. I have see issues with the crank shaft balancer it's self for the 24X sensor the reluctor ring on the blancer being damage from road debit getting cuaght in it etc... those are the only things that come to mind. Also when ever you need electronic parts for an engine do not buy aftermarket parts get them right from the dealer you save some $ but the parts as a rule are JUNK!  Also the guys at autozone are "parts guys" not technicians their job it so sell parts not diagnose problems. If I were a betting man My guess is there is an issue with that harness for the &X sensor or even a bad ground wire connection on the engine block buy the transmission. good luck :)