1994 gmc cuts out at 55mph
engine runs fine when parked will rev to red line in 1st, 2nd, but when it reaches 50mph in 3rd or 4th it cuts out and won't run.
Take a look a the Crank Shaft Sensor...http://troubleshootmyvehicle.com/gm/4.3L-5.0L-5.7L/how-to-test-the-crank-sensor-1
You may also want to check PCV valve, O2 sensor and catalytic converter, check and clean the throttle body..
its more of a backfire and missing than a stall.
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