I know my check list is extensive. However, those are the things I would start with. If it has been a long time since the last tune up, pull a plug and see if it is worn. Also, check the air filter. If it is plugged, it will run rich. I would next move to the coolant sensor. This sensor is designed to tell the computer both ambient temps and coolant temp. From that info, the computer determines how rich or lean to make the fuel mixture. If the sensor tells the computer it is colder than it is, it will run rich.
Last, check the fuel pressure. It may be allowing too much pressure to build.
If the check engine light is on, have the computer scanned for trouble codes. That may identify where the problem is without you having to check anything. Just so you know, most nationally recognized parts stores will scan it for free, so that way you can save some money. However, if you live in CA, they passed a law so the parts stores can't do it. I still can't believe it, but that is what I was told.
Friday, February 11th, 2011 AT 3:53 AM