Running rough at idle.
 

Hey guys,

My 95 850 non turbo has developed a strange issue. When stopped at lights idling for longer than about 45 seconds, my car seems to stop running on 5 cylinders, giving little coughs and generally running like poo.

As soon as you take off it runs rough for about 2 seconds then runs all good again.

I am going to look at spark plugs and leads/distributor tomorrow in day light, but anything else I should look for?

There is no CEL or error codes.

If anyone can point me in the direction of where I should start looking that would be great.

Thanks :)

When was the last time the cap, rotor, plugs and wires were changed? Thats the first thing that came to mind, the second was a dirty injector that eventually spits into the engine instead of atomizing.

The plugs were changed about 8000km ago (about 5200 miles)

Unsure of the cap, rotor or leads. I havent had the car all that long.

Will start there, and maybe put in some injector cleaner.

Well I've put in a dose of injector cleaner, and have noticed a considerable improvement. Might book in to get my injectors professionally cleaned.

The other thing to check would be the vacuum line coming off the fuel pressure regulator if you have a regulator up on the fuel rail. If there is any fuel in the line or a strong smell of it you have a ruptured fuel pressure regulator which would also make the engine run rough by being too rich at idle but less noticeable once it took off and gained some R's.

You could also clean the Mass Air Flow (MAF) sensor attached to the air filter housing, make sure you have a clean air filter and remove and clean the Idle Air Control Motor and the Throttle Plate. They all contribute to a good idle.

I dont have a regulator on my fuel rail Kiss, and my throttle plate and air control valve were cleaned about 3 months ago. I cleaned the MAF as per your idea, I reckon between that and the injector cleaner it seems to have done the trick, thanks guys for your help.