1992 325 possible electrical problem

Anyone ever experience a 325i of the 1992 era missing on a cylinder (or similar sensation)? This symptom is accompanied by a whining sound on AM radio that increases in pitch as I accelerate and decreases as I slow down.

The car has 105,000 miles on it. Please tell me it is something simple and not expensive. I still owe $3300 on it and would rather not add anymore into it.

Thanks in advance!