E30 Zone

Hi all, my M20B25 has a strange revving problem, it drives fine up until 3.5-4k rpm then it just coughs and splutters and won't rev any more. Sometimes it idles at 1k other times it idles nicely around 650-700rpm.

I thought it was fuel pressure related due to a noisy fuel pump, but I replaced that yesterday, and I still have the problem.

Can anyone help please?

I had similar problems, turned out to be a clogged up fuel filter. Not revving to a normal limit means your not getting enough fuel or air.

Others have suggested fuel filter too, although I have changed mine recently, I will change it again, its due another service soon.