Cold starting problem

[wellfan]

My 8 valve Gti has been very reluctant to start, when cold, for past few days. It seems to catch on 1 or 2 cylinders and then on all four. I checked the plugs and they are a bit 'sooty'. The car runs great and starts well when warm. The problem coincides with me replacing the thermostat (old one had been stuck open for months, car now runs at correct temp.). Could my engine now be running too rich now that the engine is running at the correct temp? Any thoughts. Also which way do I turn the CO screw to reduce the mixture content?

[thedentist55]

First off, I would replace the plugs, especially if you are not 100% sure when they were last changed - people in the old days used to remove plugs and warm them up to get cars started so that might fix the problem.

If the CO mixture has not been adjusted at any point during your thermostat issue then it shouldn't be running too rich, and I wouldn't mess with that unless you have an exhaust analyzer like they use when you get an MOT. If your still concerned about the CO get a garage to check it for you, shouldn't cost much.