It started misfiring badly recently half way into a journey, out of the blue. Neither I nor my mechanic can work out why.
It idles fine and up to 1500 revs everything is normal. Another 500 revs and it misfires but by around 2000 revs it stops missing and runs fine. Then at 3000 revs and up it starts again. Every time you ask the engine to work a little harder than very gentle cruising it starts misfiring badly.
We’ve tried taking the air flow sensor out and that didn’t seem to make any difference. Also we replaced the plugs, leads and coil packs and that’s not sorted it either.
It’s a 1991 318is (M42b18). Thanks, really want to get back on the road.
