Loss power code 43

Asked by Homer Nov 27, 2019 at 10:54 AM about the 1994 GMC Sierra 1500 C1500 SLE Standard Cab LB

Question type: Maintenance & Repair

Truck is throwing 43 code. Not the
knock sensor, new cap button EGR
solenoid,wires plugs, it's fine till third it
will shift to third then bogs down and
loses power, tries to die when stopping
unless I let of of gas and hit it again
then it stays running and does fine till
third again. Doesn't do it in overdrive
but doesn't shift to third either. Please
help. No leaks in vacuum either did the
spray test with carb cleaner

2 Answers

157,945

For kicks and giggles, check to make sure the connection on the knock sensor is tight. If it is the lets put a timing light on it and see if you are at 0 Degrees or if you are at 4 degrees retarded while the engine is up to temp. if that's the case you may have a bad knock sensor. On a cold engine check the the ohm resistance on the sensor it should be 3500 to 4000 ohms...

I'll have to find someone with a timing light to do it I know that it moves back and forth I seen a video that said it shouldn't do that idk I know I unplugged it and once I got to temp and hit third gear it started doing the same thing.

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