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burnin oil · 06-15-2020, 06:10 PM

If the condition only shows up after the motor has been running awhile it may be the ignition module. After years of service the dielectric grease breaks down and gets hard. Once this happens the module doesn't use the distributer body as a heat sink anymore and will overheat. You may want to get another Delco module and throw it in the glove box. I had a couple modules go bad that showed the same symptoms along with a coil going bad. The little brush under the coil can be the wrong resistance and cause the coil to overheat but this is usually only a problem with an aftermarket ignition. If the truck acts up and dies on you then will refire after 15 minutes or so and run normal I would look at the module. I also had a carb that would run rich on the secondaries and break up after being floored for awhile. Let off the gas and count to three and it was back to life until you floored it through the gears again.

06-15-2020, 06:10 PM	#24
burnin oil Registered User Join Date: Jan 2013 Location: Eastern TN Posts: 1,921	Re: 78 Suburban surging then dies on long grade If the condition only shows up after the motor has been running awhile it may be the ignition module. After years of service the dielectric grease breaks down and gets hard. Once this happens the module doesn't use the distributer body as a heat sink anymore and will overheat. You may want to get another Delco module and throw it in the glove box. I had a couple modules go bad that showed the same symptoms along with a coil going bad. The little brush under the coil can be the wrong resistance and cause the coil to overheat but this is usually only a problem with an aftermarket ignition. If the truck acts up and dies on you then will refire after 15 minutes or so and run normal I would look at the module. I also had a carb that would run rich on the secondaries and break up after being floored for awhile. Let off the gas and count to three and it was back to life until you floored it through the gears again.