Bogging and stalling while driving

[Invisible Saddle]

well here is background info
- '86 325e
-stock motor
-recently did seafoam treatment fuel and crankcase only (not vaccum line yet)

Before I did the treatment I would get an extremely hard jerking and sputtering from the engine when I gave it more the 35% throttle. I have even gone as far as to sit parked and rev the motor. Intermittently at times it will stall or rpms will drop considerably when I give it more then 35% throttle. This occurs from idle to redline.

I have checked for vacuum leaks by using carb cleaner and nothing is amiss. Tomorrow I will change out the spark plugs and cap n' rotor. I'm feeling it could be a spark issue although at times the motor behaves perfect. I will go ahead and change out the fuel filter as well. I highly doubt it is a fuel feed issue though.

Could anyone point me to possible areas of concern. Thanks.

[JSiN]

check the cam sensor wire..... i had the same issue, and it turned out to be the wire had come loose from the retaining clip its supposed to be in, and started slowly getting chopped by the radiator fan, until finally bare metal was showing thru the insulation, and it would make contact with metal on the engine, causing it to ground out or something.... not exactly sure of the specifics, but its worth a shot....check it out....
hope that helps, if not now, maybe later....