2013 X5 35i Random misfire problems. P0300

[Vonbimmer]

Ard is right on target, Bimmergeeks Protools is an android based app that reads specific codes and allows you to monitor and log live data. Sorry for the confusion I must have been thinking of another post where the poster had the Protools app.

[ard]

Can you pull your AFR readings???? Something like a Foxwell520 should read that.


If your fuel trims are whacked out, could be telling you fueling is a problem- too lean or rich, can cause misfires that move around.


(A DME detects a misfire by looking at the EXPECTED acceleration of the crankshaft and the MEASURED acceleration- when it sees a mismatch it says 'misfire'. As these are small variations and you get a slew of oscillations and readings with each revolution, sometimes a miss on one cyl shows up as a neghboring cyl. (Newer DMEs are better these days.) But in a car that has a lot of misses, you can see this apparentl 'moving around'.)


How many miles? Original O2s? Any other notable history??

[bojan2512]

Ok so i took the car to a mechanic and he says the fuel pressure is arond 70psi but then it goes to -70. Is it possible for the fuel pressure sensor be bad? Is it possible for the fuel pressure to go negative? I dont think it is correct me if im wrong

[ard]

what did the mechanic say, in terms of why there is a -70 psi reading?