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I've been chasing this for a few weeks now. The code started popping on the way home from the dyno tune after I put in a TSP 228r cam in my 02z. Tuner deadened the tables a bit more but the code persisted. Initial troubleshooting found the spark plug gaps OOL so i changed those to pregapped bosch 9602's...code stayed. Checked resistance on all plug wires and tested the coils...all checked good. Adjusted my rattling exhaust (long shot for a fix). I just noticed today that my harmonic balancer is a bit wobbly. Now I've read that the crankshaft position sensor is what triggers the p0300, and if the crank pully is out of balance, the whole crank could be vibrating. Would a wobbly HB be a feasible cause to the p0300?
The tuner seems to think otherwise. Regardless, its bad so it will be changed. If THAT doesn't fix it, I'm going to start looking at the drive line for damage and wear. The car only has 48k miles on it so I'm not expecting anything from that side though.
If you'll be inspecting the drivetrain I'd look at the TT Couplers...a great video below if you want to gain a little more knowledge on this subject !!...and BTW if you do change the HB have your tuner perform a "crankshaft variation relearn" !!...do you actually "feel" a misfire or you just throwing a P0300 ??
If you don't actually feel misfires and the engine is running smooth as silk I'd do that crank relearn first and if your tuner has a scope I'd have him look at the crank sensor...it could be bad !!...if he doesn't have access to IATN to pull up some "good" waveforms this is mine off my 2001 !!
...don't worry about the highlights...I like to color...LOL !!!
I got my harmonic balancer changed out. Feels like it idles a hair smoother, but the light still came back!!! It seems to happen only when the exhaust is droning (around 1500 rpms). Checked all the wires and plugs......again. Also, not sure if this is just the nature of the camshaft, but the idle isnt consistent. As in, the lope sounds like it speeds up and slows back down while remaining at a steady 800 rpms. I'll be visiting the tuner again next week. Any ideas on where to look next would be mich appreciated!
P0300
