I'll make this quick...




Compression test good...
New wires
New plugs
New coils

Idles goes into closed loop, then randomly goes into "Fuel System Error" at the same time as P0301... when flashing SEL goes off vehicle back into closed loop. P0301 at the same time as Fuel System 1 Status (8) Error. OBD2



Any thoughts? Fuel pressure? Injectors?

 

I’ve had misfires and o2 sensor errors when my fuel purge valve would stick open dumping vapours into engine.
Replaced it with the Hyundai part

 

What settings did you use on OBD fusion to get your trends to show up like that?

 

or misfires from out of spec MAF....

 

imported the cvs log file into excel and the graphed it.

 

brand new Bosch MAF...

 

Given it comes and goes, I would suspect the purge valve as well. Vapors will cause engine to run a little rich - normally the ECU compensates by dropping injector pulse width but if it is leaking - maybe? You can see from the 02's it actually does go rich at that point.