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Dieing Under Load

janschutz

janschutz

Corn Hauler
When at a stop light, car in gear, and the AC on, the the 351W is stumbling and sometimes dies. If I turn off the AC or put the the C4 transmission in Neutral, the engine then run smooth. I have checked the coil and alternator and timing. which are fine.

The alternator is a 65 amp, is that too low? What else to check. Someone at the local car gathering said I should go with a high amp 1 wire alternator. Looking for input please
 
I don't think the alternator has anything to do with your problem. Sounds like the idle is set a bit too low to handle both the "in gear" situation and the AC on at the same time. It should idle 600-700 rpm in gear with AC on. 900 or so at idle
 
I had a similar problem on my car when it was automatic. Ended up being the voltage regulator. Check that
 
I would eliminate the fuel filter as the potential culprit by changing it out for a new one.

Z.
 
I had issues with stumbling. I replaced the working PVC and the rubber grommett, and It took care of alot of those issues. The PVC seemed good when you took it out it moved freely, and rattled around. It was the grommett that had hardened and was a slight vacuum leak. Caused a stumble that I chased for a long time. This is an easy, cheap fix.
 
My 302 does the same thing when it idles in gear. Starts to stumble and will sometimes die if I don't slip it into neutral. It doesn't do it all the time and it will do it when cold more often than when at operating temp, but it will still occasionally die at a stop light. It's embarrassing when trying to leave a cruise-in or show because it will definitely die when cold and with the power steering cranked over full stop. I've got the idle cranked up to 900. I've got no idea what the alternator is doing because I've got the stock ammeter that hasn't moved in the almost two decades I've owned the car.
 
Got it figured out, it was the coil. Put a new MSD Blaster Coil and now it runs great. Increased my MPG by a little over 2 MPG on my road trip.
 
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