I have a 1985 190E 2.3 and it has been having a weird problem

it starts ok, but when I let it idle, it miss fires every once and again. now, that in and of itself wouldnt irritate me, but when the car is standing at a stop light in drive, the engine miss fires and stumbles so much that the engine actually died once.

I have hooked my vac gauge up to the engine and it all seems withing spec, but I keep having a feeling its vacuum related.

worked perfectly one day, miss firing the next.

any ideas guys?

would hate to have to sell the car.

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