Hey all, need a little help. I've read through a bunch of these misfire threads and haven't seen any that match mine. I just acquired a 99 Jimmy sport sls. Looking to get it running better before I sell it off. Most people say it's the spider as the cause of a misfire on these, from what I've read. Mine doesn't quite fit the common symptoms, hard cold starts, lean, what not. Mine will fire right up almost instantly. It runs rich. Drives down the road fine, doesn't feel like it's lacking power. It will burn the tires off of it. The engine light is on and flashes going down the road. I haven't checked the codes yet, won't have a scan tool until Monday night. I don't know much about the truck, what I do know is the motor and tranny has been replaced, plugs and wires have been replaced also. The cap and rotor haven't. I don't have a fuel pressure gauge so I can't test the pressure. Any ideas on what it could be or things to check would be great. One other thing is the throttle body is gummed up pretty good, to the point the gas pedal is hard to push at first. Thanks for any help.