My 2002 SC2 coupe has an intermittent no crank no start issue. Will go several days and stop and start with no issue then suddenly wont crank or start. All bells and whistles come on when you turn the key but wont crank over. Go back the next morning and it starts up just fine. Don't really want to just start throwing parts at it. Any ideas where to start?

 

I would remove and clean battery, cables, clean battery terminals, inspect the cables for corrosion near the connector to the battery, and ensure that the non battery end of the ground black wire is making good contact with the frame of the car on an unpainted non corroded surface..

Next, check the battery connection at the starter remove and clean any corrosion on the connection or where it bolts to the starter.

Have your charging system load tested. Your battery my right at the min limit of current to start the engine.

Also the next time it has an issue at home jack up the front of the car put on jack stands take a long piece of pipe lean it on the starter case and hit it end on. Actually is accessible from underneath the vehicle so you can just go whack it with a hammer. If your starter is failing, this will usually knock loose but the part that is hanging up and preventing the shaft with the starting gear from sliding out to the flywheel, engaging, and rotating the engine.

Do not replace starter unless you isolate it as the cause.

 

Okay, battery okay, cables and wires cleaned and tightened. Car has not gone into no start again but now it refuses to idle, Am I looking at a crankshaft position sensor here? Cranks starts then immediately tries to die. As long as I am pushing on the gas it will run okay but when I try to stop it dies.

 

As previously suggested, get your charging system checked for FREE at AutoZone or similar. The voltage supplied to the ECM must be at or above a certain level or all bets are off on proper operation. Any combination of failing battery and compromised alternator can create a situation where the ECM does not consistently receive the min required voltage.

We'll explore other possibilities once any other charging system issues are determined and addressed and the charging system is given a clean bill of health.

Otherwise we're throwing parts at it, which is both illogical and costly