[brian7]

I have a 1993 GMC 1500 has a 4.3 TBI (non vortec). recently it has started running with a slight miss. It is more pronounced at light throttle like to drive through a parking lot.

I have put a cap and rotor on it, O2 sensor, plugs, ohmed the wires as they are a year old. I also changed the fuel filter. this is all within two weeks. the truck has 100,000 on it and i ran a decarbonizer on it about 5000 miles ago. any suggestions?

 

[member12]

I have a 1993 GMC 1500 has a 4.3 TBI (non vortec). recently it has started running with a slight miss. It is more pronounced at light throttle like to drive through a parking lot.

I have put a cap and rotor on it, O2 sensor, plugs, ohmed the wires as they are a year old. I also changed the fuel filter. this is all within two weeks. the truck has 100,000 on it and i ran a decarbonizer on it about 5000 miles ago. any suggestions?

The plugs, wires and distributor are new, the O2 sensor is new, and you changed the fuel filter...

Is the check engine light on? Maybe you've got an injector not working correctly. I had a 95 silverado that would run rough unless I was using higher octane gas at least every other tank.

 

[nicolet]

Inspect the distributor mainshaft for the pickup magnet integrity...

Make sure your EGR is free & not sticking...

 

[ChevroletTough]

Inspect the distributor mainshaft for the pickup magnet integrity...

Make sure your EGR is free & not sticking...

DANGET Sonoma!! haha, you always beat me to the punch! I was going to suggest the same thing. I bet the distributor shaft is the culprit. I need to replace mine as it has the same symptoms. I'm almost positive that it is the distributor shaft.

 

[nicolet]

DANGET Sonoma!! haha, you always beat me to the punch! I was going to suggest the same thing. I bet the distributor shaft is the culprit. I need to replace mine as it has the same symptoms. I'm almost positive that it is the distributor shaft.

Sorry, my friend!!!!


Considering the mileage...if the mainshaft is gonna be replaced (if it's bad) spend the cash and replace the pickup coil & igntion module as long as you are inside the thing...

 

[brian7]

the check engine light isnt on, and the ignition module and the pickup coil are a year old. im going to hook it up to a scanner today and look at the fuel trim numbers just to see which way it is going