Help Scotty. I own a 2009 Pontiac Vibe 1.8l auto with 240,000kms on the body but 125,000kms on a used engine. When the car is in gear and I turn the heater fan on full speed the car stalls, but stays running if it’s in park or neutral. It takes about 4 or 5 tries to restart the car after this happens. If I shut the car off normally, it starts right back up again.
Parts replaced: coils, fuel injectors, MAF sensor, Crank sensor, battery and ECU.
why did you replace all those parts?
I'm not a mechanic but it sounds to me that your alternator is not putting out enough power.
are there no mechanics where you live that can diagnose the issue?
that wouldn't explain why it only happens in gear
I just replaced those parts to make sure the car ran perfect for my daughter. She had to drive 3 hours to school.
I took the car to my local GM dealer, they had it for 2 weeks trying to figure out what was wrong with it. They finally said it was probably the computer, so I replaced the computer and it still does the same thing.
When I owned a car with a 4 cylinder engine, there was a solenoid near the throttle linkage that would energize and bump up the RPMs, revolutions per minute, of the engine when the air conditioner compressor was turned on so the engine won't stall. AC compressors take a lot of power from engines which is why MPG drops when driving with the AC on. You might investigate to see if you have such a gizmo on your car to keep it from killing the motor every time you turn on the AC. If you do, it might not be working like it should. It doesn't die while in park or neutral because no power is applied to the drive train so it has plenty of torque to spin the AC compressor when activated. While the car is in drive, there is some energy going to the transmission and without some more engine speed, the AC makes too much resistance for the engine to overcome and dies.
This engine doesn’t have an IAC on the throttle body, it is all computer controlled. Also, it will stall when I just turn the fan on high with the AC off. I tested the alternator and it always puts out 13ish volts with the fan on high. Now, it doesn’t always stall out when the fan is on high, it is very intermittent, sometimes it does, sometimes it doesn’t. Since I have replaced the computer, I haven’t put any drive time on the car, just sitting in my driveway testing it.