Hello,

Thank you in advanced for any help and insight. I have a an 03 GTI 1.8T for about a year now. Occasionally after running it will not start back up. Engine will just turn over. If i wait a minute or 2 it will eventually fire but will run rough and smoke from the tail pipe(white) for a few second then snap out of it and run normal. The only code the ECU is displaying is a Engine Coolant Temperature Sensor malfunction. Is this sensor causing the starting issues or something completely different?? Thanks again for any help.

 

The coolant temp sensor could be it. It registers the temp to determine the amount of fuel is needed. In the old cars it was a cold start valve actuated by the temp of the coolant, so if not working properly there wouldn't be enough fuel to get it started in the cold. The system is different now but acts the same. Yours may be opposite in that it's dumping too much fuel because the computer thinks it's cold because the sensor is bad. Good luck

 

Thanks for your help. That makes sense as the smoke that comes out right after start up smells strongly of gas. I'll look into getting that sensor replaced. Thanks again.