Once it starts doing this, how does it idle in "park"? If you have the misfire there, and it's constant and steady, pull off one spark plug wire at a time to see if you can identify one that causes no change in how the engine is running. If you find one, suspect the spark plug or wire, or even the rotor and distributor cap. Also consider a wobbling shaft in the distributor that is allowing the air gap to change for the pickup coil. You can find that by using an inductive-pickup timing light with the probe on the coil wire instead of a spark plug wire. You'll see the light flashes cut out intermittently.
If the periods of cutting out are more random and last longer than a single misfire, fuel is the likely issue. It's rather time-consuming but you may want to tee in a fuel pressure gauge. I've been running with one clipped to my radio antenna for over a year since I was chasing an intermittent problem. I just left it there to watch. You're going to need an older gauge that reads pressures typical of a carburetor system. That's up to five pounds of pressure. Newer fuel injection systems commonly run over 50 pounds. Those gauges won't even move at five pounds of pressure. If fuel pressure starts dropping when the problem occurs, the main suspect is the sock on the end of the pickup tube in the gas tank. The clue here is restarting the engine. Stopping the engine and fuel pump gives the screen time to stretch back out and open up. The engine will run fine again, but each time the problem will occur after less and less time.
Tuesday, February 4th, 2014 AT 2:16 PM