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1997 Chevrolet C1500 4.3L V6: P0147 and P0300 Codes - Diagnosis and Fixes

Model: 97' 4.3L Fault Code: P0147 Posted: 2015-05-11 09:55

I own a 1997 Chevrolet C1500 with a 4.3L V6 engine. I've already replaced the spark plugs, wires, distributor cap, oxygen sensor (Bank 1, Sensor 3), and the catalytic converter. After checking the wiring harness, I noticed a missing circuit connection. This has been causing either a P0300 or one of the P0301-P0306 codes to appear, along with a P0147 code. The check engine light doesn't stay on continuously—it only comes on intermittently. I use a basic OBD2 scanner (cheap model) stored in my truck and clear the codes when they trigger. I'm not sure what to try next, but since multiple codes appear together, I thought others might have insight into what could be causing this issue.

Related fault codes
P0147P0300
Comments (4)
Anonymous 2015-05-11 10:51

Check for 12 volts at the oxygen sensor location. Note that 'CIRCUIT' is mentioned in the P0147 description — refer to OBD-II code reference: http://www.obd-codes.com/p0147. For P0300, start with a fuel pressure test. With the engine off and key on, observe how quickly the pressure drops (should not drop more than X PSI in 3 minutes). Only use AC Delco spark plugs — Bosch plugs can trigger P0300 codes.

Anonymous 2015-05-14 00:57

Have you checked the vacuum ports on the intake manifold? A leak here could cause misfires and related diagnostic trouble codes.

Anonymous 2015-05-15 11:36

Fiolater wrote: 'I've replaced the spark plugs, wires, cap, oxygen sensor (Bank 1, Sensor 3), and catalytic converter. I noticed a missing circuit in the wiring — this leads to P0300 or P0301-P0306 codes along with P0147. The check engine light comes on intermittently. I use an OBD2 scanner and clear it when needed. I haven't tested fuel pressure yet, and I don’t have a fuel pressure regulator installed — I'm leaving town temporarily and will return to test these components.' I suspect the P0147 and one of the P0300 codes flashing together may point to the same root cause. Since replacing the catalytic converter didn't resolve it, that suggests the issue isn’t in the exhaust system. I believe a fuel pressure regulator or vacuum leak is likely involved.

Anonymous 2015-06-26 12:31

FIXED: The problem was a cheap plastic distributor from GM. Replaced it with a metal distributor and all codes cleared. No more P0147 or misfire codes after the replacement.