Mis firing 98 e36 M3

Question

Hi - Have a e36 m3 with 174000 miles-had the check engine light on for last 10 years

so never paid attention to it - i knew it was the o2 sensors .Car ran fine

Had a massive rain storm here 1 month ago drove through some water that was not that deep but next day

car had a misfire . My FIXD scanner said all 4 O2 sensors need to be replaced so replaced all 4 o2 along with the maf hose

before the throttle body and the ccv hoses and valve as they needed replacing .Cleaned MAf and trottle body as best i could

with the specific spray cleaners/did not take off the throttle body to clean back side

The car runs fine/great for a mile or 2 then check engine goes on and runs rough with a slight misfire

Now have P1250 low fuel pressure , along with codes misfire cyl. P0304,p0305,p0306 and code p0300 "

"combustion misfire several cylinders"

I have spent $500 on parts and my time - could i need a new fule valve regulator now -Or am i chasing parts ?

Thanks Alan BMW

Dion · Answer

I think if you take care of P1250 - low fuel pressure that would take care of ALL your missfires P0300 and P0304-P0306. Don't know why you did not get P0301 to P0303 unless they are not experiencing low fuel pressure. Odd. But then again I'm not a beemer tech!

alan BMW · Answer

Thanks - really appreciate your follow up

I am wondering if its possible a fuel flow valve gone bad also causing the P1250

as its under the car some what exposed and my issues started after driving through a bit of water

I called a local mechanic and suggested replacing all the coils, but the low fuel flow would still be there ?

At 65.00 each and i need 6 don't want to rush in the wrong direction - still have same issue

Thanks