E46 misfire

Hi there I'm new to this site but have been on alot of diffent forums for the different cars that I have owned

I have been using this site to sort out various things with my car and I must say that it has been very useful :-)

I have had my tank explode on me and I have just finished replacing all the subframe bushes

The issue I now have is that when it's been running for about 20 minutes it developes an awful misfire on cylinders 4,5,6 it's ok when I clear the codes but comes back after a little while sometimes it will misfire on cylinders 2,4,5,6 but never on cylinders 1,3 ?? I have checked for an air leak and there is nothing another search said it could be the aircon pump but I really don't understand that !!

So has anyone got anymore ideas to help resolve this problem ??


Matt

Could we please get the year and present mileage of your vehicle; with that many misfires it indicates an issue concerning either a vacuum leak or a MAF issue. You stated you checked for vacuum leaks. What exactly did you check, did you pull the lower intake boots to inspect them for cracks and holes. Help us help you...

I'd bet money the smaller hose coming off the lower intake boot has cracks in the accordion.

It also really helps if you post the codes when you know what they are....

Originally Posted by Zchild

Could we please get the year and present mileage of your vehicle; with that many misfires it indicates an issue concerning either a vacuum leak or a MAF issue. You stated you checked for vacuum leaks. What exactly did you check, did you pull the lower intake boots to inspect them for cracks and holes. Help us help you...

hi there i have not checked the lower intake boots where are they ???

and my car is a 99 with 121 thousand miles the problem started after the car was serviced

the codes are

P0300

p0302

p0304

p0305

p0306

Originally Posted by E46_330i_Stud

I'd bet money the smaller hose coming off the lower intake boot has cracks in the accordion.

is that the pipe that comes from the air filter ???

it might be that because when my header tank exploded it broke the air filter box off of the wing..

Originally Posted by Scrivy

is that the pipe that comes from the air filter ???

it might be that because when my header tank exploded it broke the air filter box off of the wing..

yep that is the one!
it comes from the air filter to the throttle body!

any other codes youre getting that you didnt post??? can you double check?

if the damage is before Maff sensor its ok but if it is post Maff that is an issue

this is the boot

Nope no more codes just the ones I posted :-) fingers crossed it's on the easy side!! I will have a look when I get home

Originally Posted by Scrivy

Nope no more codes just the ones I posted :-) fingers crossed it's on the easy side!! I will have a look when I get home

i loaded a pic. for you

hi thanks for the picture ive checked it all and its all fine but when its running i can hear a hissing with another car i put a valve in a jar top and pressurised the system and listened for a leak that way can i do it with this car aswell ?

323I's are a pain in the a*s when It comes to misfires, I replaced my maf, coils, fuel injectors, intake boot, ccv, fuel filter and had a smoke test done after everything, still didn't fix the problem. Do you know what was done at 100k maintenence? My misfires were finally corrected after replacing my precat o2 sensors. I only had misfire codes too nothing pointing at the o2's

nope my car has no history from that time as the guy i got it off serviced it himself i might do a smoke test as i can definatly hear something that is not right and it that fails i will replace the precat sensors thanx for your advise on this