The Vette stalls. Basically it will start perfectly fine and will run fine for a little while. It will run smoothly without any codes untill the engine gets hot.
Once the engine gets hot the ignition cuts out and the engine stalls. Same code once again: Code 42!
like I mentionned before, I had the ECM replaced before the winter. I did a complete tune up while it was parked for the winter: spark plugs and wires, PCV valve, Cap and Rotor, Air filter.
Before storring her for the winter I had a problem where she would be very long to start. To fix this a garage changed my ECM and at the same time also changed the coolant sensor and the oxygen sensor. That fixed that problem and the Vette starts right up. Now When I took her out a couple of weeks ago she was not shifting and I had the tranny rebuilt. Was driving home from the tranny shop everything running smoothly at about 80mph on the highway when it suddenly started missing. Then the check engine came on and the stalling problem started. Seems it will run fine untill the engine gets warm then it stalls. The ignition just stops! Now its not the alternator or anything. The alternator tested and averages 13.8 volts. But the rest of the electrical works. I mean when it stalls, the fan and radio and everything else still works. The mechanic checked the distributor and it looks fine. We changed the EST module in the distrobutor, the ESC Module, and everything ignition seems fine. He repaired a harness and all other harnesses seem fine and most even new. Pins and connectors all seem fine. What could this be??????
I mean the final possibility on the diagnostic chart of a Code 42 is FAULTY ECM. My ECM is brand new. Before I change that anybody have any idea what this could be?????????????
Any help would be greatly appreciated. Somebody on another forum suggested the distributor main shaft might be magntised???
Chris

 

Does the '84 have an ignition control module (ICM)? On LT1s, a code 42 is usually a faulty ICM and your symptons sound just like it.

 

Had a similar problem with my '84. Changed the Ignition Control Module & it fixed it. It is a $20 item. Pop the distributer cap to access. Takes about 15 minutes to change. Can't hurt...
In the interest of cleaning house, I hear the MAP sensors can do this as well...
Then again there is always that pesky fuel filter or fuel pump.
Good Luck!

 

I know this is an old thread, but i would sure like to know what the fix ended up being. I am having that same issue today.. Think is, I recently replaced the entire distributor, however, Code 42 was not getting thrown, but had been having the stalling. Found that one of the injectors, driver side was missing an o-ring. Replaced both injectors, with new o-ring, been running fine on my short test trips, though on a longer trip today and it had the occasional stall symptom. Let it cool down for a couple hours, went to start and wants to run bad and has code 21 & 42. I did bump the voltage down on the TPS due to code 21 means high voltage on the TPS. That is a new TPS, and getting the feeling it might not be so great and thinking the electronics inside are changing values as the temps heat up.
Have not replaced the ICM or the map sensor yet.

Thanks

 

I'd check the grounds at the back of the heads.

 

Well, I actually fixed the problem this morning. The car has had the stall problem since I bought it last year and I have replaced.. you name it. Complete distributor recently, plugs twice, wires, fuel injectors, TPS, etc.. fuel pump 3 times, the tank was very rusty on the inside and more.
Anyway.. the solution to Code 42 for me was exactly what the code is calling out and that is the Electronic Spark Control Module. I didnt replace it, though thought to pull the connector this morning and found that 1 of the connectors was very corroded and obviously was making poor connection to the connector. I removed the module and took 150 grit sand paper and cleaned off all of the pins on the module. Dabbed some dialectic grease to all pins and re-connected it back up. The car started up very quickly after that and ran alot more responsive than it has been. Went on some long test runs, tallying up around 100 miles today with it and not a single stall or misfire.
It is that module located on the passenger side, beside the windshield washer bottle. Hope this helps someone in the future.