Today on my way home from work my car was driving fine, despite the fact I need a new Crankshaft Position Sensor. Well as I start running into rush hour traffic I start to take off (normally) I realize the rpm's start going higher than normal (about 3k) and then it shifted. The Service Engine light started flashing (it was already on due to the CPS), flashed for about 20 seconds then stopped. Car shifted like that about twice within my 50min drive home from work. Doesn't feel like the tranny is going out, it shifts very smooth and have yet to have any issues with it. Could it be related to the CPS?
BTW Today was the first day this has ever happened.

 

service engine or check engine?

check engine flashing is usually a misfire

 

I only have a service engine light. I did read something that the CPS can cause this.

 

So what's the code?

 

For the CPS

 

Shifting problems can happen with from multiple issues. First of all, check your transmission fluid.

Scan the car for SES codes.

It wouldn't surprise me if the TPS was going bad causing your shifting issue. Don't count out the solenoids in the tranny.

Crank sensor failure has the potential to cause shifting issues, but it's more likely to make the car die when it warms up.

 

In tune with what Nitehawkjcb shared, look into spark (as in plugs, wires, coils) as well.

But if your CPS is bad, if I understand how that works, that, in ITSELF will cause mis-firing. If the car is mis-firing, with a computer controlled trans, it opens up to a lot of issues. Get the CPS fixed and then work on the rest.

An example of what I'm talking about (mis-firing and shifting issues), in '05 my friend and I took his '94 Firebird on a trip from our home (Northern Ohio) to Bowling Green Kentucky. While there, the car began having shifting problems (and we were hoping to make it home). Due to his knowledge of the drivetrain in that car, he suspected a failed Opti-Spark (GMs replacement for a distributor in '94). His car was ball part 50,000 miles, Opti's fail around then. We got home, week later, car no start. End of this story, Opti's died! Replaced, all good.

Fix the CPS, see if everything clears.

 

Thanks guys I will be getting it fixed tomorrow after work at my buddy's house. Gonna stop at the auto parts store pick up the part then replace it! I am 80% sure the CPS is causing the issue because the car ran perfectly fine up until it triggered the CPS engine code.

 

Keep in mind, I think you have to do a Crank Position Relearn after changing the CPS. That will require a scan tool like a GM Tech II in order to initiate.

 

Good luck witht he fix, let us know how it goes.