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68gmsee · 09-25-2014, 09:15 AM

Just as an fyi; Bad gas can cause the symptoms you describe and can lead you astray in trying to analyze the problem.

Other possibilities; Using the old resistive wiring on an HEI distributer. It needs full 12vdc.
Sparkplug cabling crossed.
Vacuum leaks. I unplug all the vacuum lines -power brake booster, automatic transmission- and plug them up as a test.

If all the above are okay and you're not sure about the fuel in the tank: Buy a 1 gallon can of fresh gas. Place it under the truck under fuel pump. Remove the inlet rubber hose to the fuel pump and replace with app. a 2 ft. fuel hose going into the one gallon container.

09-25-2014, 09:15 AM	#5
68gmsee Active Member Join Date: Jul 2007 Location: Centrally located between Houston, Austin and Waco. BCS area. Posts: 7,947	Re: motor runs bad please help Just as an fyi; Bad gas can cause the symptoms you describe and can lead you astray in trying to analyze the problem. Other possibilities; Using the old resistive wiring on an HEI distributer. It needs full 12vdc. Sparkplug cabling crossed. Vacuum leaks. I unplug all the vacuum lines -power brake booster, automatic transmission- and plug them up as a test. If all the above are okay and you're not sure about the fuel in the tank: Buy a 1 gallon can of fresh gas. Place it under the truck under fuel pump. Remove the inlet rubber hose to the fuel pump and replace with app. a 2 ft. fuel hose going into the one gallon container. __________________ 68 GMC 250/3 speed Saginaw p/b p/s 69 Chevy 350/350 currently in pieces still lookin for a cab 06 Trailblazer I just want a vehicle that I can work on, that won't talk to me, leave error msgs or keep track of how I drive...