W124 rough running at low revs

[DriftworksJames]

Wondering if anyone can shed a little light on a problem I'm having.
Over the last couple of months I spent driving my 1988 260E around I noticed every now and then it would misfire when pulling away at low revs, but would then be fine for the rest of the rev range. This only happened every now and then.
I've left the car sat for 2 months and it's started fine, but since then it's misfiring all the time over about 2000 revs it seems fine, but less than that, it's not firing on all cylinders it seems.
I took it for a wash and it just wouldn't start afterwards, turned over fine and got spark and fuel up to the injector control box thingy with all the pipes coming out, but just turned and turned and wouldn't fire. It was a pressure washer, but I was very careful not to blast it through the grille and the engine bay wasn't wet. After waiting 30 mins for a friend to come and tow home I gave it 1 last go and it started ok, but is misfiring badly under 2000 revs all the time now......

I suspect it's either a damp/worn/knackered rotor or dizzy cap or something up with the fuel injector control box thingy.
Anyone had a similar problem?
thanks,
James

 

[Ian B Walker]

you might want to check the vac lines going to the inlet manifold. if one has come away it will be belleding air into the system. Happened to a 190 I once had, wouldnt run at anything less that 3000rpm. Also look at the top of the injector unit. Is the round flap seated level?

edit...........try using some injector cleaner, might help

 

[DriftworksJames]

thanks Ian, yes the airflow metering flap is seated properly and doesn't look gunked up. I ran a load of injector cleaner through about 6 months ago.
Broken vac hose would make sense, might check the rotor and dizzy cap as a matter of course, cos they're easy and (I hope) relatively cheap