02 Tahoe, 223k miles. 5.3 4wd. Changed oil on 5/4. Drove about an hour on the interstate 5/9, half way there it started misfiring. Code was P0300 random misfire and P0452 fuel tank pressure sensor circuit low voltage. Advanced recommended to replace fuel injector pressure regulator. Replaced the sensor and P0452 went away. P0300 still there. Now suggestion was to start with a tune up. Replaced spark plugs and wires, still P0300. Replaced crankshaft position sensor, still misfiring. threw code P1381 so cleared codes and tried a relearn crankshaft. Still throwing code P0300. No other codes at this time. should I replace the regulator? Fuel pump? I don't want to keep changing random parts, dumping more money into it that I really don't have right now.
02 Tahoe P0300 code
- Thread starter Sarahwv
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@Sarahwv Moved you here from 2015-2020 section.
Welcome from Miami!
Welcome from Miami!
rockola1971
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Need to get a fuel pressure reading at the rail at idle and part throttle and before engine crank but key on. Whats your readings? Verify in real time with a scanner misfire counts for each individual cylinder.
Just an update on this - ran a complete diagnostics. Fuel pressure was normal. Cylinder 5 had over 20,000 misfires on record, cylinder 4 had 1500 on record. Replaced ignition coil on 5 and misfire is gone. Ordered another to replace 4. Check engine light is gone and car is running better. will replace the ic on 4 when it gets here.
Mine, 2013 Tahoe, kept having the same issue. I changed the brain box, but it took 3 months to figure out that it was the box.
SnowDrifter
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What are your short and long term fuel trims?
