FeedNfrenZ

I'm trying to mix a problem on my 1985S that I've just sold to my brother-in-law................ (I still service it) It has a slight miss at idle. I've done the rotors, caps, injectors, plug wires, hoses and timing belt what should I look at next?

AO

What about the plugs themselves?

How does it run at speed? If fine, I'd tell my brother not to let it idle!

SteveG

Engine warm or cold?

Green Goblin

How about vacume lines, that should help quite a bit.

Andy

FeedNfrenZ

Plugs changed, vaccume lines replaced (not to say their is NO leak at all) and it idles the same hot or cold runs fine at high RPM (but harder to tell if that's true)

Beth

We have the exact problem with our '85! It's a very faint miss and it's only at idle. I don't know how much Rich has dove into it, but I do know all vacuum lines have been checked. Next we were going to pull the plugs.

I'll be curious to learn what you find out!

FeedNfrenZ

I'm thinking timing and/or coil?............... what about O2 sensor?

jpitman2

Localize it to a cylinder by selective shorting of leads. Then move that plug and see if miss follows plug or not - if yes replace plug. If no, swap plug lead - if it follows, replace lead. CHeck dist cap for internal tracking/arcing - swap caps, see if miss follows cap. Once I had a miss when cold on a car where spark was fired by a small bar magnet in distributor running past a pickup. I changed plug, stayed there; changed lead, stayed there;changed cap, stayed there.Closed up gap to pick up from .016" to .014", problem went away - weak bar magnet. In 928 case last resort may be crank angle sensor - magnets in flywheel, pick up clearance?
jp 83 Euro S AT 48k