Intermittent rough running/cutting out.

[sunbeam alpine]

I have a 1990 2.0 litre Alfa Spider (fuel injection) which has started having a small but annoying problem. It drives fine most of the time, but then will start cutting out when stopped at lights or in traffic, and then it runs rough (misfires etc.) for a while. It seems to cure itself, and sometimes it doesn't do it at all (I drove it all day Tuesday and it didn't do it once, then yesterday it did it twice on a short run).

It never does it when the engine's cold, and normally starts when idling in traffic - if you're stuck in traffic and standing still for a while. I don't believe it's a cooling issue as the temp gauge doesn't go higher than usual. Could it be related to the radiator fans kicking in and drawing too much current?

So far I've swapped the spark plugs and distributor cap (can't swap the rotor at present because it's fixed on a shaft and has to be ordered specially). This hasn't cured the problem.

I'm starting to think maybe a problem in the fuel supply somewhere, but I have absolutely no knowledge of fuel injection systems.

If I disconnect the electrical cable to the MAF, the engine stops immediately. Could the MAF be faulty?

Anyone have any ideas?

[marshalla]

If you've swapped the plus and dizzy cap - have you also swapped the HT leads ? These can break down and cause intermittent misfires.

[sunbeam alpine]

marshalla said:

If you've swapped the plus and dizzy cap - have you also swapped the HT leads ? These can break down and cause intermittent misfires.

Not yet. Would there be any advantage in "premium" leads over bog standard ones?

[marshalla]

sunbeam alpine said:

Not yet. Would there be any advantage in "premium" leads over bog standard ones?

Not as far as finding out if they're the problem is concerned - a fresh set of leads will always be better than a tired old set, unless they're really really poor quality.