e36 320i erratic tick over thirsty no power

[buzbee]

Hi all, new member alert!
recently bought my 320i and after a good run on the motorway something has gone wrong, im new to these cars and have no idea where to start
symptoms are... on tick over revs dip from 8000 to 5000 about evry 3 seconds then jump back up again.
very thirsty on juice
when driving under load feels like the engine is missing.
sparkplugs are sooty
and a noticably drop in power
its had a new MAF senser before i bought the car, air filter is reasonable, checked all the plugs for sparking and there all ok.
any suggestions much appriciated!!!!!!!!!!!!!

[witeshark]

How many miles on the car?

[buzbee]

96000 miles

[jmo69]

I would have guessed intake boot crack but the sooty plugs indicate running rich.

[denyo77]

the ticking noise and loss in power could come from misadjusted valves
but that wouldn't cause the rev fall nd such a huge power loss

[buzbee]

Originally Posted by denyo77

the ticking noise and loss in power could come from misadjusted valves
but that wouldn't cause the rev fall nd such a huge power loss

sorry, should of said tickover as there isnt any ticking, engine sounds good and smooth apart from the revs dropping evry 3 secs

[buzbee]

Originally Posted by jmo69

I would have guessed intake boot crack but the sooty plugs indicate running rich.

yes, would definatly agree with it running rich, checked the plugs when i first got it and the where a nice brown colour, its only since the engine problem started that bthey have gone black and sooty.
havnt had time to have a good look around yet but ill check that soon, was thinking it could be a sensor but i dont know how to check them or narrow it down to which one it could be?

[basrite]

Hmm..

The revs jumping around is what mine does when the aircon is switched off.. goes from 800 to 500 and bounces for like 3 seconds then settles around 600 and smooth.

It stopped doing it briefly after an aircon regas. Not sure if it was related or not?

J.

[buzbee]

Originally Posted by basrite

Hmm..

The revs jumping around is what mine does when the aircon is switched off.. goes from 800 to 500 and bounces for like 3 seconds then settles around 600 and smooth.

It stopped doing it briefly after an aircon regas. Not sure if it was related or not?

J.

The weird thing about mine is the rhythm of the rev change is really precise and in time? just been talking to my uncle who was a mechanic and he recons its either the idle speed control valve or the MAF sensor so gonna check it out tomorrow!
p.s no aircon on my model