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P0300 and P0507 Diagnostic Issues on 1997 Blazer with 190,000 Miles

Model: Blazer Fault Code: P0300 Posted: 2008-01-16 14:12

I own a 1997 Chevrolet Blazer with 190,000 miles. I have already replaced the idle speed control sensor and the accelerator positioning sensor. The vehicle runs smoothly under normal conditions, but when stopped at a traffic light, it stumbles without dying. This issue persists despite these replacements. Any insights or troubleshooting steps for P0300 and P0507 codes on this model would be greatly appreciated.

Related fault codes

P0300P0507

Comments (3)

Anonymous 2008-01-16 16:57

A potential EGR system issue could be responsible for the P0300 code. Have you actually tested the electrical circuits or have you only replaced components based on recommendations? The forums are full of theories about P0300 on Blazer models—checking actual wiring and sensor signals is crucial.

Anonymous 2008-01-16 19:27

I followed advice from a $5.00 mechanic who suggested replacing parts without diagnosing the root cause. Now, new suggestions point to the distributor or spark plug coils, but I'm losing confidence in that technician's approach.

Anonymous 2008-01-17 09:41

I recommend searching specific forum threads for P0300 and P0507 on 1997 Blazer models, as well as consulting the official vehicle repair manual (phonebook) for accurate diagnostic procedures.