Hi all, I've got what I think is an in-tank fuel pump problem on my daily driver 1980 242 DL (Bosch K-jet CIS system). Problem is, it's an INTERMITTENT problem. Hesitation and lugging on acceleration, when hitting dips or bumps in the road, or under hard cornering. Sometimes I hear a buzzing/whining/humming noise coming from somewhere under the rear of the car (possibly from in the tank?). Sometimes the problem "goes away" for days or weeks at a time, and at times the noise and hesitation and "trailer-hitching" lasts for days or weeks at a time. It seems to come and go randomly.

Is this a problem with the in-tank fuel pump, or is my problem something / somewhere else? I'd like to get an accurate diagnosis on this BEFORE dropping $$ on a new in-tank pump and dropping the tank too... I've got almost no experience working on K-Jet CIS systems, all my fuel injection experience is with L and LH EFI systems. Any input will be greatly appreciated...