bmw 318 e90 p0304 cylinder 4 misfire detected

Question

when start motom i slowly rpm 700  motor vibretion and rpm 700 not
stable.check all pluge,coil,injectars,lackag,all i good.
check i injector 2 wairs ,  one +  and one- flshing , this - flashing when present motor ok  after one minet ,- flashinge end  not flashinge and motor vibration that is cylider 4 not good .
thanks...

Answer 1

Hi there,

Check engine compression on cylinder #4. Also, swap coil #4 with the one next to it and see if the misfire moves with it. Sometimes coils fail when under load but test fine on the bench.