2004 saturn ion quad coupe

If the problem is temperature-related, the mechanic is never going to find it if he keeps the car all day in a heated garage. Have him keep it overnight either outdoors or in an unheated building, and check it in the morning when it's cold.

The only time you take your car to dealer is when you have engine driveability problem. This is the case. I know Saturn Ion has the anti-theft sensor built in the ignition switch. When the ignition key is turning the sensor inside the ignition switch (passlock switch) read the reistance and send to the Body Control Module (BCM) and allow fuel for starting. If not reading the correct resistance it will cut fuel and enter security tamper mode by not injecting any fuel. When this happens and secuurity lock is display on the instrument panel cluster. The resistance in the ignition switch sometimes change slightly at lower ambient temperature. I think this is what you are experiencing. This problem can only be correct by replace the defective passlock switch and program the BCM by the dealer.

I have a 2003 QC. There is a known problem with these symptoms- cause is bad lubricant used in the ignition switch. I had mine replaced by the dealer. All is well now. I thought yours would be in warranty until 36,000 miles.

Bill K.