Slight Misfire Problem 325Ci 2001 ?

[woolley2021]

hi guys im new to the forum and new to the world of bmw's :) im trying to diagnose a misfire problem without spending a fortune , i have a recently purchased 325ci 2001 m54 which i have had a new 66k engine fitted along with new genuine maf due to old engine having head gasket failure , ive noticed on idle it sounds like a slight misfire so had it plugged into snap on diagnosis machine and it showed up misfire cylinder 1,2,3,4,5,6 ive just gone and unplugged one coil at a time and they all seem to drop the revs and when re connected bring the cars revs back up ... so do you think it could be a spark plug issue ? any help would be great thanks james

[Guest Mister Dabsy]

Do you think its running rich? Have a smell at the exhaust fumes...

[woolley2021]

Yes it does smell very rich tbf ?

[Guest Mister Dabsy]

Maybe the MAF then... Are the engine breather pipes clean/clear? This could also cause richness or unburnt fuel if clogged as it will be gagging for air !!

Check all the spark plugs as they tell a story ;)

[woolley2021]

The maf is brand new bosch im missing a pipe from the air intake boot you should have 2 pipes coming from the F looking peice im missing the bottom smaller one ?! Where does that go it looks like some sort of vac pipe maybe im not 100% ?

[Guest Mister Dabsy]

TBH the receiver to that must be blocked off or the part that it supplied has been removed... There is no need for vac in these engines except for brake servo, as the timing advance/retard is controlled electronically (and the fuel system too) !

I would check and clean all the engine breathers... You will see an improvement ;)