P0300 won’t go away!!!

[Schurkey]

Drive to Nevada, buy a universal cat at Summit Reno. Get it installed. Bribe the inspector if needed at the next CA emissions inspection, 'cause you're probably not going to pass if you don't--no CARB certification paperwork.

This does not get better, in fact it's in the process of getting MUCH WORSE. Until Libttaard politicians get thrown out of office for Treason, what's good will become bad, what's bad will be more bad, and what's terrible will become normal.

Or just buy legal cat(s), and avoid the hassle.

 

[1998OBS]

I’ll start a GoFundMe page for two catalytic converters. Everyone who commented just send $5!

 

[DerekTheGreat]

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[Supercharged111]

I’ll start a GoFundMe page for two catalytic converters. Everyone who commented just send $5!

Even if the cats are junk, you'll just kill the replacements if you haven't for sure gotten to the root cause.

 

[1998OBS]

Even if the cats are junk, you'll just kill the replacements if you haven't for sure gotten to the root cause.

Don’t tell me that… lol

 

[Supercharged111]

Don’t tell me that… lol

I do have a better idea: leave Commiefornia. It'll be cheaper in the short and long run. But seriously, easiest/cheapest way to nab stock cats is a parts truck.

 

[1998OBS]

Just an update: I won’t leave anyone following this post in the dark, once I figure this out I’ll definitely post what it was…

Right now I’m throwing:
-P0300 multiple random misfire
-P0155 O2 sensor heater element

 

[Schurkey]

Right now I’m throwing:
-P0300 multiple random misfire
-P0155 O2 sensor heater element

Did you ever determine if the P0300 is real, or false because the scan tool won't report individual cylinder misfire?

Time to screw in a fresh O2 sensor. When that was me, I put in all four.

 

[Supercharged111]

Did you ever determine if the P0300 is real, or false because the scan tool won't report individual cylinder misfire?

Time to screw in a fresh O2 sensor. When that was me, I put in all four.

I threw a heater code a couple years ago, sensor wasn't but a year old. I fixed it with a hose clamp, the ground lug solder joint failed.

You must be registered for see images attach

 

[1998OBS]

You must be registered for see images attach

Here’s some new:

I connected a scan tool to it and found out that cylinders 7 & 8 are both misfiring simultaneously. I don’t know how to read the rest of the info but here it all is for anyone who’s more familiar with it. I did find a vacuum leak at the EGR valve and corrected it, not misfiring as bad as it was but still getting a P0300, the O2 sensor code went away without any change there other than correcting the EGR vacuum leak…