Long time no see fellow jbody.org'ers, im trying to help my dad out here with this one. Hes got a 1993 cavalier vl with 200,000+ miles on it. At idle when he starts it in the morning, its misfiring badly. In cold weather has been the only time i have seen it happen, today we have 60 degree+ weather out and i went to take a look at it, and the damn thing started right up fine. I can still hear a little misfire at idle but nothing like that he had before where it would barely stay running. Whatever it is the warm weather seemed to help the situation. Ive gone over all the basics but some things i couldnt find were specs on resistance for the spark plug wires and ignition coil to check and see if they were working properly. There is a bad gad smell under the hood, although my scanner tells me that the air fuel ratio is normal and that the o2 sensor is also showing normal #'s. Unfortunately i dont have a list of basic specifications in voltages and such to do testing on some sensors and what not with my multi meter. I also found a broken vacuum hose in the rear of the engine that i cant find where it leads to...any information you guys can provide here would be most helpful, including specifications on things.

Wish I could help with the vac line but,mines way too old and different.Being the car started fine and ran ok in warmer temps are maybe the egr valve.This will not set any codes,intermittent etc.I would pull it off and clean it with brake clean and make sure if it has the metal pintal that would move up and down it moves freely(use liquid wrench or bp blaster) and clean all the carbon out this effects the emissions and can make the car run rich if it is sticky or loosing vacumm due to the diaphram inside is worn out.The only other thing is the temperature sender going and not reading properly even if the gauge (if the car has one is ok on the reading) this would cause the car to run rich.Unless one of the injectors is failing or a bad wire going the plugs (would not rule out) I would clean the egr and replace the wires and see if any change.That's what comes to mind right off.If the car has the 2.8-3.1 eng the injector specs are 11.8 -12.6 ohms and if a 4 cyldr with one injector 1.2- 1.6 ohms.I can't find the resistance on the plug wires in my books right now.Hope this helps at least give u little info to consider.And just in case the fuel pressure for tbi is 9-13 and for multiport injection is 26-32 psi.OK