91 camaro idles for a few min. then dies

My brother has a 91 camaro RS 305 TBI. A while back it was having charging problems so we jump started it to get to the parts store it died on the way there so we had to jump it again but then it wouldn't start at all, towed it home realized there was no fuel to the injectors, we replaced the alternater and battery to take care of the charging problem then the ECM for the fuel problem. It ran fine for 2 days then it started to slowly overheat then sputter and die. I jumpered the aldl and read the flashes it was flash flash flash flash pause flash flash, thats 42 right? We replaced the coil and reset the ECM, but no change we decided to take it to a shop at a dealership and they did what we were trying to avoid and started shotgunning parts at it. They replaced the knock sensor, ignition control module, electronic spark control module, thermostat, coolant temp sensor. and now they're baffled (not exactly what you want to hear from a certified mechanic) last contact with them they were going to check the cat. conv. Can anyone think of anything else or is the mechanic on the right track with the cat.?
It's been in the shop for 2 weeks and its too nice of a car to be off the streets that long.

Is there any more info that might help??

Much appreciated, myBrothersKeeper

I'd have to check my code chart to see what #42 relates to, but there's no way that the e.c.m. can set a code for a bad coil. The coil is a controlled device and w/that computer system, the e.c.m. can't determine the coil's status. It was probably still good so that was a waste of money and labor. It sounds like the dealership that has your car is about the same caliber as the ones here. They are only parts changers and have no idea of how to diagnose a problem and fix it w/only the minimal parts needed. Since the problem hasn't been fixed, they need to remove all the new parts that they threw on it, put the old ones back on and credit your account.
I can usually diagnose a problem within 15minutes. If it takes longer than that, there's usually more than one problem or the problem is more serious than minor.

How long does it take for the temp to get above normal (210*+ w/a 195 thermostat), does the cooling fan come on?
Sputter and die? Need a better description of how it dies. Does it die like you turn the key off, does it slowly idle down and die, or does it try to die a few times and the cut off? How does it run when you drive it? Have you checked charging voltage?

Looking at all the parts that were replaced, I'd say it might need an ignition pick-up coil (a bad one can break down when hot). Does it run cool on the highway and then heat up when idling? Bad fan motors are pretty common. Need more info.

Well the day we changed the coil it was about 15 min of normal in town driving before it started cutting out and that was from a complete cold start to just above normal operating temp, just before it dies it acts like it runs out of fuel but I assure you that there is fuel in the tank. As for the cooling fan it comes on at start up runs for a couple min then shuts off and is intermittent after that sometimes it would come on when warm and sometimes it would not. But get this the other day I went to the shop to check on it and the tech just got done installing the ignition control module he started it up seemed to idle ok meanwhile I was monitoring the temp gauge and it was only at about 180 when it started cutting out then died.
The sputter and die is more like it tries to die a few times then cuts off.
It does seem to have a loss of horsepower in normal driving.
I was watching all guages during our 15 min test drive and the voltage was reading normal I think it was 16v but I might need to double check that but I do know that its at the same level since purchase.
As for running it on the highway we never got a chance to get it on the highway because we didn't trust it enough to take it out. From what I can tell it would probably act the same way on the highway.
Hope this helps
btw - I believe 42 is EST (electronic spark timing) and during my research I've heard it reffered to as "the dreaded code 42"
also I have been trying to get the tech that is working on it to tell me what they're computer says is the problem but they won't tell me they just dodge the question then say it's just leading them back to the ECM.

I've been dealing with the new OBD-2 systems (the new generation of computer systems) for so long that I can't recall my years of experience on IROC's/Firebird's (F body?) systems if the code 42 is from disconnecting the timing connector. You might make sure that the brown/black harness connector is indeed plugged in. Have you shot the timing? It calls for 0 degs., I usually set them up to 2/3*. Even if it was out of time, it still shouldn't die.
I have a box of good used parts and sensors that I can swap out while diagnosing a certain problem. My main selection is G.M. ignition modules. I can swap one out in several minutes (if I think it's the problem) w/o having to purchase a new one, saving myself the money. If I purchase a part, and it doesn't fix the problem, I don't charge the customer for the thrown-on part. I'll leave it on until the vehicle is fixed, then I'll put the old one back on. There has been instances where there has been more than one problem, so leaving the new part connected actually fixed a problem that I wasn't aware of.

I have seen the distributor pick-up coil cause some screwey problems. I had a Suburban that kept eating a module every 12/14 months. It cranked over, but wouldn't start. Put on a "tester" module and it would run fine, so a new one was purchased. After the 3rd time, instead of a module, I replaced the pick-up coil. It's been fine for the last 4 years.
I had a truck come in that wouldn't start sometimes. It would be fine for 2/3 weeks, and then it wouldn't start, but the next day it would. He left it at the shop, I drove it and ran it every day for 2 weeks, it did fine. He took it and drove it for a month and then he came back to have a u-joint checked out. I got in to drive it, it wouldn't start. It didn't have any spark, so I put in my tester module and it started and ran fine. A few minutes later it cut out and ran, then it cut out and died. I replaced the pick-up coil and that took care of it.
My next guess. Since the coil, module, and other parts have been replaced, take a close look at the coil wire then try the pick-up coil. That would be the next logical choice. The only bad thing is that it's not an easy job. When diagnosing a problem like yours, I rule out the pick-up coil last, because it is hard to do a voltage test/replacement.

The fan? It should only come on when the a/c is on or when the fan switch reaches 215 to 220 degrees. If the fan is triggered by the ecm, then the computer has to see the 215-220*+.

Fix the running problem then concentrate on the cooling system. If there's any doubts about the thermostat, replace it with a Standt Superstat 180* replacement. I always drill an 1/8" hole in thermostats to bleed the air out of the system, so make sure that's done too.

Let me know what happens.

Problems that occur after the motor has warmed up usually point to a failing ICM, which can test good one time and bad the next so test it several times. I also thought about the wire not being connected all the way. Lastly, fuel pressure?