Hey Scotty. I've been struggling with a CEL ever since I got my car (2004 Nissan 350z). It started off with a p0300 code which was for a random cylinder misfire, so I changed my spark plugs and coil packs, which didn't fix it, so I changed my fuel injectors and my intake/ plenum gaskets, which then changed the code to a p1273 code. Since then I have changed my fuel pump assembly (includes the fuel pump, fuel regulator, and fuel floaty), both upstream O2 sensors, intake vacuum lines, and PCV valve. Everything intake wise is tightened down completely and I hear no leaks. I have yet to clean my MAF, which I am going to do tomorrow when I get a chance, I just watched your video on it. I have no idea what the issue could be if this doesn't fix it and no forums/ mechanics in my area can tell me whats wrong(EVEN THE NISSAN DEALERSHIP). I'm thinking I could need a tune or something but I just really have no clue what the issue is. I wrote up a list of mods I have done to my car and my whole story of whats wrong on the google doc ( https://docs.google.com/document/d/1Imu-oQUayIMwKXTUyEBHvC2L698ako7MVA6u1bdK9U8/edit ). If you or anyone else has any idea of what the probable cause is please let me know I'm tired of this CEL and need my car registered by the end of the month. Thank you! (My email is DG_Hook@yahoo.com)

Comments
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Believe231
Believe231

It could also be an exhaust leak, have you checked it closely for any leakage? But it may simply be that the headers will always set off that code if the stock a/f sensor isn't able to operate as it did with the stock exhaust system.

DGHook
DGHook

I was thinking of installing a wideband o2 though

DGHook
DGHook

I don't have a scan tool capable of reading live data

DGHook
DGHook

Could the headers do it? Because the code was on there even before I got the car and that was the only modification done to the car before I got it

ScottyKilmer
ScottyKilmer

you did a lot of mods, and unless the computerr was reprogrammed to accept those mods, it will never run correctly. BUT, do try cleaning the maf and realize mafs go bad all the time on those and you might need a new one. Analyzing its live data would show a lot if you have a scan tool

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