1994 gran prix 3.4 cold start problem

[phatmax]

I have a 94 Pontiac Gran Prix GT with the 3.4l quad cam. I have been having issues with it starting when cold. When it starts, it immediately stalls, this happens quite a few times when very cold outside. After a few starts/stalls, it will stay running, but very rough, bad misfires, popping through intake, smells like fuel. I have checked while running rough after it starts by pulling plug wires away from plugs and 2 cyls. in front bank were dead. Still had strong spark from wires, just no change in idle when pulled. Also what really irks me is that after 10 or 15 minutes of warming up, the car runs like brand new. New wires, plugs, coils, ignition module, ECT sensor and computer have all been replaced in past 6 months. Also replacd timing belt if that matters? I need help badly, it is my only car and dont have money to take to shop as it is close to x-mas and it is getting worse as it is getting colder and colder.

[tblake]

Are you able to ohm check the injectors?

I'm not sure of the 3.4DOHC is batch fired or synchronized. If batch, then if one injector shorts out, it will drag down all the others on that circuit because electricity always follows the path of least resistance (through a shorted injector).

If you can check resistance. They should all be roughly 12ohms. A littler higher should be ok, but any lower and they are shot.

[phatmax]

Thank you, I will check them hopefully be early next week as I work all weekend. If one or both were shorted, would they clear up once they are warmed up, because like I said in post, once the car has ran for 10 or 15 minutes, the car runs like brand new. I have pulled plugs out just to make surre car wasnt flooded and it was not, just smells like raw fuel when cold, have even had people tell me it smells flooded, but never is.

[tblake]

Hard to say. I have heard injectors run good cold, but short out as they warm up. I am not sure if it can go both ways, but I guess its worth a quick test.

Obviously you have two dead cylinders. If your car runs fine once warmed up, then I'd be willing to bet mechanically the engine is fine.

Next step would be to swap the coil packs around and see if the dead miss's follows a specific coil or if it stays at the same cylinders.

You do have good spark when the motor is cold, right?

[phatmax]

Yea, it has good spark cold, when I pulled wires out, I check gap it would jump, and in meantime I got bit pretty hard. Needless to say, has good strong spark. I have an ohm meter but will not have time to get into it till after the weekend. Really cold outside and no garage so hopefully it will be a little nicer by next week after work. Thank you again for your information.