Evilfrog

My cobalt has developed a problem. Sometimes it won't start. You crank it, and it doesn't fire. Or when it does fire it back fires. If I let it sit for a few moments, it will start right up.

Once it starts it runs fine for the most part. There are no backfires, it revs all the way to 7,000 without any issue. It does have an idle issue though. RPMs will drop sometimes below 500 RPMS when coming to a stop with the clutch in. The car will figure it out sometimes and the RPMs will come back up. Other times it will die.

Also, the Tach seems to be flacky whenever it is having this issues. I've had issues in the past for whatever reason the tach and speedo don't seem to work. But this was always rare and restarting the car would fix it.(I'm talking once a year rear.)

So I'm thinking the PCM is just losing the crank position. Does anyone agree with this? They are only a few bucks, But i'd hate throwing a ton of parts at it.

steelmesh

You should get a code when the PCM loses track of the crank or the cams.