As the title states I have a 1991 318i and the idle will sometime jump or surge even while driving. I have already searched this forum as well as r3vlimited and e30tech and bimmerworld. I checked the harness without taking the upper manifold off because the gasket between upper and lower is in the mail.

I do NOT get a check engine light but the car seems to misfire or surge completely randomly. It's almost as though I have a tank of bad gas but I have refilled the tank several times and even added fuel injector cleaner and get the same result. The strange thing is some times I can go a whole day without it ever surging at idle or misfiring while driving.:confused: This is very annoying as the car runs perfectly and gets awesome gas mileage besides this. Any info/help would be awesome.