I have an 89 Z28 with a 305 TBI. My issue is when I start the car, it will usually die the first time. Start it again, and it fires up and runs rough for up to 5 minutes. Almost sounds perfectly timed rev/die/rev/die/etc. Would this be something simple like cleaning up the TBI? A sensor somewhere? Or a potential fuel pump issue? My fuel pressure gauge also reads 0 when cruising if that matters. Thanks in advance for any advice!

A TBI is supposed to run with 11-13 PSI fuel pressure. I've seen them run with 8 PSI, but not very well. Before doing anything else it would be good to verify the actual fuel pressure. I'm guessing it is low and also guessing that something is amiss with your pressure gauge.

Could be... when you did it, did it help?

Doing the SOOOOOOOOOPER EEEEEEEEEEEZZZZY CHEEEEEEEEEEEEEEEP stuff like that before presenting things as an unsolved mystery always seems to pay off, for some reason. A much better plan than inviting losers like Vader and me to guess at it over the Internet, while you already know what you can do about your issues.

Start there.

Sounds like it might not hurt to check and see if your coolant temp sensor is hooked up properly, and if it is, swap in a new one, since the problem seems that it might be temp-related (although you don't say so, but the customer complaint seems to be related to initial startup). If the ECM always thinks the engine is warmed up, then it won't run right when it's not but might work better when it is.

Is it hooked up at that time? i.e. taped to the windshield etc.? (as opposed to, say, laying in the back seat floorboard ) How did you hook a gauge up to it? There might be a clue to its behavior in that detail somewhere. In any case, since a FI car can't possibly run with zero fuel pressure but your car is evidently running well enough to cruise, it's an absolute certainty that the gauge is reading wrong, and that whatever reading it gives, is totally meaningless and should be ignored for the purpose of diagnosing the car. Kinda defeats the purpose of a gauge in the first place I know, but ya gotta go where logic and reason take you.

Thanks for the advice guys. I haven't been able to work on it yet but will this weekend. I'll get the TB cleaned up and I've already replaced the CTS on the front of the manifold. I guess I'll replace the 2 in the heads as well. I will hopefully post some positive results!