I own a 2004 saturn ion redline it has a problem some where ok I have ahd it to the dealer twice now and thhe problem is still there ok what the car is doing the idle is going up to around 1500 and then it is dropping down to about 300 somtimes the car even stalls now it does not do this all the time but it is always when i am sitting still the dealer said it was the thermost and they replaced it and it is still doing the same thing the print out on the codes said there were several EVAP codes what is a EVAP code? I was wondering if you could give me any help toward the right way to fix this problem?
sounds like a throttle position sensor.
Evap codes are the evaporative emissions system, a closed system that returns evaporated fuel vapors to the fuel tank. It's possible you have a vacuum leak in that system which is causing problems at idle. There's no reason the thermostat would cause any of that. Throttle position sensor is a def. possibility and get those Evap codes checked out with a Miller smoke machine or similar device to see if there are any leaks.
Buy a new throttle body gasket since you'll have to take off the throttle body and clean it completely including the butterfly valve. Also clean in the snout of the supercharger but for the snout spray it on the microfiber cloth first, NEVER inside the supercharger. Reinstall and i guarantee the problem will go away.
It's the Purge Solenoid for sure.. GM Part Number: 12597341 AC Delco Number: 214-1678 Hope this helps!
The EVAP purge solenoid on that particular engine is infamous for having internal failures in the diaphragm allowing vacuum past causing a stalling condition. If it were me id check that and the IAC motor in the throttle body assembly for sticking issues. The throttle body gasket leaking wouldnt cause a stalling condition let alone EVAP codes.
my redline used to have the same problem and i take it to the mechanic and and he put all the holes brand new and has problems stop he also fix a leak on the manifold now the car is running fine