I have a '91 Firebird with 305 T.B.I., and here are the symptoms. It is generally hard to start, but the colder the worse. When it does start the idle surges to about 1500 then comes down to about 0 and either dies or surges again. when put in gear it can die or stay alive, but until the engine warms up it runs really rough. I have to give it gas and then let off and sort of feather it. If I slam on the gas it will do nothing, the tach stays about the same, but then all of the sudden it powers up and takes off. It does great on the highway and once it warms up. after it is warmed up though and I shut it off. It runs really bad after i restart about 45 minutes to an hour later. Sometimes i have to wait 5-10 minutes before i can get it going. It was really bad, but I put a new cap and rotor on it, plugs and wires, and it really helped. I also had the fuel pressure tested, it was fine. About six months later it started up again, although not nearly as bad. I put a new cap and rotor, and plugs, but no wires. It didn't really help, but advancing the distributor helped a little. the wires don't seem to be burnt or anything, but I plan on swapping them soon. I had the ignition module tested, and it checked out. The ignition coil was tested for resistance, and it looked okay. I was going to put a new one on anyway, but i didn't have another bracket for it. I plan on swapping out the distributor and coil as soon as i get the parts, as well as pulling the IAC valve to have a look, but if anyone has anyother suggestion i could really use the help. Thanks, and I apologize for the length of this post, but i figured i'd get everything out there.

 

Leroy,

Meter the ignition wires before you replace them.

Test the fuel pressure. Your symptoms have a ring of "lean" to me. You'll have to get or fabricate a pressure test adapter to check the fuel pressure, since TBI installations did not include a Schrader valve for pressure testing (how cheap is THAT?). Operating pressure should be between 11-13 PSIG on a stock setup. I'm guessing your's is around 7 or less, but that's just a guess based on the point where that type of symptom occurs.