Code P0300

[maxwedge]

A basic Actron like I use for quickie diagnostics pinpoints cylinder misfire, 9185, no one is saying a Tech11 scanner is required here. Just a working one.

[DeltaP]

Originally Posted by Schurkey

That's kinda my point. The REAL code delivered by a REAL scan-tool using professional-grade software would have been P0305--misfire on #5 cylinder. You'd have zeroed-in on cylinder #5 immediately.

The generic OBD II code pulled off by a consumer-grade code reader is P0300--"random misfire". You were led to dick with cylinders that had no functional problems--because your code-reader isn't capable of delivering the TRUE code. Your tool lied to you, told you the misfire was "random" when it was specific to #5.

Folks wonder why I crusade against junk consumer-grade code readers. I used the Actron web site search function, the 9235 isn't even listed.

Thats exactly what he's sayin.

[dmince]

Your right on the scan tool not zeroing in the the exact cylinder but it's better than nothing. I think it was a bill a few years ago and has saved me that many times as a Trailblazer owner . I just carry it with me all the time. From what I've read the P0300 was common with other posters and if they got a P0301 and swapped coils it gave the P0300 and did not follow the bad coil. I assume they weren't all using cheap readers also???
It was time for a new set of plugs anyway. Probably should pick up a spare coil for insurance with 186k miles on the OD.
All's good....and the Trailblazer is back in commission...Thanks to all the help here as usual.

Thanks, dmince