p0300 code

[TimMahaney]

Hi guys I just went stage 5 with my 2.0t and when I started it up got black smoke from exhaust and flashing CEL with p0300 code. My car is running rich, took out plugs to check them out. Plugs are all coated and unhappy, so rich for sure with the black smoke. I found something weird and want to know what you guys think. My upstream oxygen sensor is reading .03 volts yes .03 volts. My understanding is it should never drop below .1 volts. I thought maybe my tool but my downstream sensor is reading .45volts and that looks like its in correct range. what do you guys think? Dead upstream oxygen sensor thinking its super lean and trying to add fuel? New converter so I only ran car for 2-3 mins before calling it quits for the day.

[Dave T]

Maybe avoid stage 5? Don't look at that as a surrender.

[TimMahaney]

Maybe avoid stage 5? Don't look at that as a surrender.

why would I avoid stage 5? I replaced the oxygen sensor and everything seems pretty good and cleared up. there is still a p0300 under load but Im willing to bet spark plugs will fix that problem now that fuel trims are pretty much where they should be.