VolVette

My '75, ZZ4, A/T has been in hibernation (if we can say that in Virginia) and I started it this weekend without any problem. I let it run for 5 minutes in the driveway then took a quick (<5 min) spin around the block. I pulled into my driveway and cut it off and did some cleaning of the Vette's space in the garage. 15 minutes later, she started right up but required me to keep revving to keep it from cutting off. When I'd put it in drive, it'd immediately die during the shift from P to Drive (3). Any guesses as to what could be causing this?

DUB

Spark plug came off...bad gas, not getting enough fuel... choke not working, sticking and shutting down....not knowing the ignition you have...it can be ignition related...not knowing the RPM's...it can be a vacuum hose came off. It is hard to comment without very detailed information....unless all you have for information is all you can provide.

DUB

lowes-yellow77

This same thing happened to me sort of. I changed the plugs and wires, and put freah gas after a 9 month sitting time while I was on deployment.
I drove it about a 3 mile trip came back and it was breaking up bad kept having to pedal it to get to stay running. I thought it was the ignition module but it turned out to be the coil. If you have a multimeter you can test both. The specs will be different on name brand.

VolVette

Thanks, Dub. Let's go through the easy ones first. A little more background. Holley carb, coiled ignition. (Tuned by the Legendary Lars.) Before shutting

1) Gas - High potential since I've only started it a few times in the last few months. However, if it's the gas, I wonder why it ran for the first few minutes without a problem. I also wonder if the gas had gunk it in and clogged up the jets in the carburetor. If gunk got stuck in the primary jets, maybe that's why when I rev the engine it still runs?

2) Choke Sticking - This is very possible. Before shutting down the car, I revved it just a little bit, maybe up to 3000 RPMs.

3) Blown vacuum hose, potentially to coil --- maybe. Will need to check.

VolVette

Hmm. Coil, possibly. I'll have to check in see. The fact that it ran fine around the block and then the problems began, possibly due to my revving the engine, makes me think it is something different.

Jud Chapin

Keep in mind that when you start these cars, they should be taken out and fully warmed up. Backing them in and out of the garage or going short distances will foul the plugs since the choke is on dumping lots of gas into the cylinders. This can also create condensation in both the engine and exhaust system which can have damaging effects. Ask me how I know...

VolVette

Uh oh. Let's hope I blew a vacuum hose or the choke got stuck.

Jud Chapin

If you think this could possibly be the problem, pull one of the plugs and have a look. If it's covered with black soot, I'd replace the plugs and she how she runs.

dochorsepower

With the Holley there is always the potential of blowing the power valve. If that happened it would run rich.

VolVette

Hard to believe but the problem is back -- I have a new theory. I noticed that my alternator belt is loose. Is it possible that the belt is so loose that it's not recharging the battery? I'm not really buying that because why would the battery recover after sitting for a few hours?