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1996 S10 4.3L Engine Misfire with P1345 Code After Distributor Adjustment

Model: 1996 S10 Fault Code: P1345 Posted: 2011-03-20 16:05

I've found detailed information on this fault code, but my situation is quite confusing. My 1996 S10 4.3L engine was experiencing severe misfires and repeatedly throwing the P1345 diagnostic code. After advancing the distributor rotor by one tooth, the engine runs smoothly—no more misfires or poor fuel economy. However, once I advance it, the vehicle now displays the P1345 code. When I move the rotor back one tooth, the misfire returns and the engine performance deteriorates, but no P1345 appears. This inconsistency is puzzling: why does adjusting timing trigger a specific fault code? Can the ignition timing be re-synchronized properly, and if so, what tools or procedures should be used to do this safely without causing further issues?

Related fault codes

P1345

Comments (3)

Anonymous 2011-03-20 18:16

Based on your description and the vehicle's specifications, a worn distributor is a likely culprit. This issue is very common in 1996 S10 4.3L engines. How many miles has the vehicle accumulated?

Anonymous 2011-03-20 20:32

The engine has 187,000 miles. Before I advanced the distributor, misfires would fluctuate from day to day—sometimes worsening after a snowstorm when snow accumulated in the engine compartment. In those cases, the vehicle would fail to start and exhibit ignition retardation. Some cylinders fired prematurely, causing the starter motor to stall. The only way to resolve this was removing the distributor cap and leaving it in a heated garage for about 1.5 hours before restarting—this is where I first considered advancing the timing.

Anonymous 2011-03-21 05:13

I agree—the majority of aftermarket distributor caps on these engines are poorly made, especially those using crossfire designs. These caps often fail when damp and can cause spark misfires that affect multiple cylinders, making diagnosis difficult. I recommend replacing the cap and rotor with a remanufactured or original A/C Delco unit for reliable performance.