what causes missing out and the smell of overfueling on and off on 2003 GMC Sonoma

at first it only did it when it was wet then it ran ok for awhile. started doing it again but it was only right at start up. after it ran for awhile or shut it off then restart it would run fine. now it will start but seems to be hitting on 1 or 2 cylinders and has no power

by in Madison, IN on May 08, 2013
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3 answers
ANSWER by , May 08, 2013
scan codes and post so we can adv
ANSWER by , May 08, 2013
IF 4.3 engine, have fuel pressure checked for leak down after turning off engine. Possible injector (spider) problem.
ANSWER by , May 08, 2013
Sounds like a leaking fuel pressure regulator. Moniter with a fuel pressure guage and see if it holds pressure after key is turned off.