Misfire after rain

[zxrichie]

Hi Guys, got a ml 320 2001, and this annoying little problem. After a rainstorm, when i start it up it runs pretty poorly, when feeling the Exhaust it is a definite thump thump thump.. signs of a misfire? feels like it when driving.. Also if i stop and check exhaust its still the same. But, if i switch the ignition off, and restart, its running smoother, i can hear and feel it, Plus the exhaust is purring when i put my hand there.

Any ideas anyone. MAF maybe,? injector.? or something i haven't thought of. Oh, if i go out in the morning and there has been NO rain overnight, it starts perfect.

Regards

Rich

 

[Will]

Needs plugging in to have the codes read. Ideally Star but for basic engine faults even a generic OBD tool should read most engine codes for a misfire.

Quite possibly a bad HT lead/coil.

 

[zxrichie]

Hi, The MAF was my first thought, now here is a really funny thing. while its running lumpy and missing, if i pull over and get out, lock her with the clicker, wait 2-3 seconds, and then open her up (all doors, not just the drivers as i did at first) fire her up and away she goes, no problems...

Work that one out!!

it really is bugging me.

 

[zxrichie]

see https://www.mbclub.co.uk/forums/engine/211152-misfire-hesitatation-just-not-firing-after-rain.html for answer....