Question about 1994 GMC Jimmy

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4.3 L Vortec problem, can anybody point me in the right direction

1994, 4.3L Vortec (CPI), when it's cold, it'll run great...but once it warms up it starts surging, to the point of dying. If I don't manage to keep it running, it won't start unless it sits for about 10 minutes, it then repeats what I already said. I've changed the inline fuel filter and plugs, I've rapped and isolated the sparkplug wires, replaced distributor cap and rotor. Biggest problem is I can't find a person. manual or shop that knows anything about CPI, let alone Vortec engines. Please help me somebody!!!!!!!!!!!

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  • Oxyco Jan 24, 2009

    I've been told its the Crankshaft Position Sensor. I was talking to a guy who car pools with me and he said his brother in-law had the same problem. And that fixed it. I'm going to pick it up next weekend and see if it really does fix it. Thought i would pass on this info. Hope it helps!

  • carhob May 11, 2010

    is your check eng. light on,if yes scan it,it should point you in right dir.

  • michael ayers Mar 08, 2013

    the pick up coil or the ignition module is the problem


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I had the same problem. I replaced the in-line fuel Filter and the entire fuelpump assembly in located in the tank and the problem went away.

Posted on Oct 16, 2011

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Check the temperature sensor for the computer. it may be telling the computer that the engine is still cold and causing the engine to run too rich at warmer temps

Posted on Apr 23, 2009

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I have a 1993 GMC Jimmy with the Vortec 4.3L engine, VIN code is W. It has CPI fuel injection with a new O.E.M. CPI unit installed. My problem is that the car 'surges' during hard acceleration (such as...

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