Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hello. My name is ***** ***** I'm here to assist you. I suspect what you have going on is a somewhat common occurrence on the trucks. I suspect you're having a battery cable issue. I've seen these exact symptoms multiple times. It may be the ground cable or the positive. Do you have a digital volt meter so we can run some tests?
Sears or harbor freight should have one. Any auto parts would have one. We need to check dc voltage drop across the length of the battery cables. Depending on price of a meter, you may want to replace the negative cable, then try it, or you may want to replace both since they have known issues.
To check voltage drop across the cables, they have to be under load. The easiest way to do this is pull the injector fuses and have an assistant crank the vehicle. You'll want to check the positive cable from the battery to the starter on DC volts, while cranking. Positive end to battery, negative to starter cable connection. Then neg battery cable to neg cable end at block. You should have less than .2 volts (200 mV). Closest to 0 volts the better.
Let me know when you're ready to proceed with testing and if my description was understandable. Please take the time to rate my assistance, and let me know if you have any questions. Thanks, George