I have a 2009 Pontiac Vibe 1.8 l auto trans with 255,000 kms.Recently the vehicle will turn over for 3 seconds as it is about to start then abruptly just keeps cranking.This happens when leaving the vehicle for just 5 minutes in damp or winter weather.I called my mechanic.He advised me to turn the key around and try and start it along with either hold the accelerator to the floor while turning the key and or pumping the eccelorator to the floor.I recorded this to show to my mechanic.He put the vehicle on a scan and found nothing out if the ordinary.He also checked the vehicle out thoroughly to see if he could find anything...he found nothing.The day was still damp out and it started as it should for him.

The vehicle just had new spark plugs,throttle body cleaned,new PCV valve and oil changed 2000km before this problem started.

Any advice would be helpful as I don't want to dump this car if I don't have too.