engine started running rough

[73 ralley]

Hoping for some helpfull opinions here. My 383 was running good all day I pulled into the driveway and parked it for about 4 hrs and when I went back out to pull it into the garage it started running like someone had pulled half the spark plug wires off. I thought maybe fuel pump and filter but they are fine. It has always run like a top so I am at a loss. Carburator or electrical next? Whats my next best move?

[the_engineers]

Vapor lock? Try it in the morning.

[73 ralley]

This happened yesterday and the problem is still there doing the same thing. Is there a way to clear a vapor lock? I did open the gas cap yesterday thinking maybe vaccum build up. Still there

[Strawdawg]

did you look into the carb while it is running to see if it is flooding with fuel?   

Is the alternator charging properly so that the battery is supplying the proper voltage?"

What ignition are you running?

[73 ralley]

I did not notice too much fuel. The alternator has not been checked "yet" and its a electronic conversion

[Cooter]

Need to find out if a plug wire is breaking down or not...Easiest way is, you guessed it, pulling one at a time...Be careful, as it'll let you know it's firing real quick if you get bit by one...

[Bullitt-]

4-hrs would be long enough for the choke to close if it's automatic. Check that it's opening a bit, OE's have a vacuum pull-off aftermarkets use an electric heater. 

[Super Blue 72]

did you look into the carb while it is running to see if it is flooding with fuel?   

One of my thoughts as well.  When the car did start back up, was there any puff of black smoke out the tailpipe? 

[slsc98]

I'm "resurrecting" this thread because: a) I experienced this same anomaly this morning (only, on initial start-up after sitting a week or more); b) this thread mentions the possibility of an alternator 'tie-in; and, c) because of the other thing I experienced this morning:

Opened car door to get in and stat car and interior dome light came on, strong and bright as ever (always a good feeling when the car sits for long periods a 1/2 hour away from where we live) but, when I turned the key to start the car, the interior dome light practically went completely off!   I mean, NO JUICE to the point I otherwise would've assumed the battery was dead.

I went through this cycle (interior light strong and bright; turn key and dims; try to start and nothing) several times and, after 3 or 4 attempts, Voila! she fired up as honestly as always.

Then, I get her out on the open road and, like the original poster described, something was definitely 'wrong' -- pressing accelerator and no where close to the normal response from the engine.  Dropped her into neutral and briefly took her up to 4,500 rpm and then she behaved as responsively as always.

2 hours later (after a local cruise-in) she started up fine but, the whole lack of response upon acceleration repeated itself until I really "gunned" her.

I'm at a loss as I never had so much Asa sniff of hesitancy or type of any problem with the engine, thus far. 

I was hoping it was some bad gas but, am wondering if there is an electrical issue.

What would be a good course of diagnostics to run

IMPORTANT NOTE: I did just replace the voltage regulator several weeks ago (old one melted from back-side) but, there has not been any problems like this morning, until this morning . . .

[Chryco Psycho]

Could be anything , I would pull the bulkhead connectors & look there , check the gap in the dist between the pick up & reluctor , should be , shpuld be .008  . 
It could be a carb / fuel issue also .
 The unresponsive starter could be a bad contact in the start relay , did you notice if it clicked when you turned the key ?

[sprecks]

I'm wondering if you might have a bad float level in the carb. It may be set to high or is failing. Sounds like the carb may be flooding over and then when you clear it out by reving it up it takes a little bit to flood over again. The dome light dimming isn't all that unusual when starting. The starter draws a lot of current.

[dutch]

my first thought would be the ecu

[cudabob496]

had a new distributor rotor and cap lately?