Bad coolant temp sensor can make em run ridiculous rich. My '93 would run great and as soon as you shut it off and tried to restart, it was flooded and belching raw fuel out the exhaust. The coolant temp sensor was showing 17 degrees in the computer on a 70 degree day, even though the gage in the dash was acting normally.
I had to use a Snap On scanner to be able to see the data being reported to the computer. A code reader couldn't do it.