camshaft position sensor? mystery rpm problems
 

alright, my 2000 z28 camaro has been having some issues and they all started around when I had an viper alarm/remote start system installed. it was installed in january then my car was stored while I was at school, now I'm home and its on the fritz. To start things off my rpm gauge will randomly work then stop working. I have also noticed some power loss and decrease in gas mileage. After this happened it began to have trouble starting, sometimes it would crank for a while before it starts and other times it starts right up. The final issue has happened about 3 times. I start the car and immediately it starts revving up to around 3 or 4000 rpm's(I don't know for sure because the tach stops working) and just slowly increases from there. once it did this i turned it off and after about 10 or 20 minutes later it starts and runs fine. I ran the code and it came up saying the camshaft position sensor was bad, but the mechanics I have talked to say that doesn't quite add up. If anyone out there has any ideas as to what the hell is going on here, I'd appreciate it.

The Cam PS will cause the hard starting problems. When they fail the engine will go into limp home mode and fire all injectors at the same time. This allows you to go home but the engine does not tune the injector pattern based on engine load. The loss of power and mileage is exactly the symptoms of a dead sensor.

As for the alarm causing issues, this is not likely the only thing that happens with this alarm is they tap into the wires coming off the ignition switch and have a couple of bypass relays to bypass the start, and ignition wires.

The no tach signal could also be from the CPS going bad. I am not sure where your engine gets its tach signal but most engines get it from the CPS or ICM.

The revving could be from the IAC. Not sure but I dont think that the CPS will cause revving issues. but I would fix the CPS first and see what happens.

Massey

Cam Sensor *could* cause the revving issue too. I have a handful of them in stock and could ship out to you ASAP. Feel free to visit my website or give me a call 302-645-6221 x126.
Thanks
Kevin
www.PartsTaxi.com

I was having the same problem. The error always comes back and the car goes into limp mode - should I replace the cam position sensor?

I've had the same problem around last year this time. My IAC gave me rev issues. but it was the cam sensor that was the major problem. I agree with Massey fix your cps, but also check your IAC