Mis-fire on a ZM Coupe

[Zoroaster]

1999 ZM coupe I have an intermittent problem revs drop to about 500rpm on tickover also engine appears to be misfiring or out of sync.Had it checked on diagnostics indie BMW garage can find nothing untoward anyone out there had a similar problem . Out on the open road it still goes like a bat out of hell .Will be most gratefull for any advice.

[Mtomlin]

I had similar thing, I put it down to crap fuel, what do you run it on?

It only happened when I used low grade stuff.

Also to be honest I had a dead battery at the time so maybe that had something to do with it?

[Zead]

I posted similar a few weeks ago, most replies said clean the MAF. I haven't done it yet as I haven't had a chance. Electrical contact cleaner from Maplin is the tool, and it's easy to get the MAF off if your a spanner man

Z