My dear new friends on this Forum

Thank you to all responses concerning my grounding problem.
I have a 1998 940 wagon b230FK with M90 gbox, 350’000 km, but want to do 1’000’000😎

Since a month I have the problem of a hesitating motor when I accelerate. It is not constantly a problem, but regularly. Then motor lacks of power. Have difficulties to go up hills. The starting and idling is ok (700 - 800 tours/min). But when I accelerate, motor is stumbling, like a donkey who does not want to go forward. At the beginning it was only after hours of driving, all of a sudden started. Next day better, sometimes hesitates more other days less. A week ago I had the engine light going on (problem of motor...). Then when I disconnected the minus/ground off the batterie the engine warning light went off, but the motor behaved worse and after about 50km became a bit better again - I did that twice - same result.

Ok, since I was reading what could be wrong. Here is what I did:
I kind of hoped that my hesitating and jumping motor was due to this broken ground cable, no !

- changed mass air flow meter (used part, hoping that it is working correctly
- new petrol pressure regulator
- changed Knock sensor (with used part from my spare Volvo 940) (doubting the right tork though - apparently if not correct tork gives wrong reading). But I will order new one just to be sure
- checked air leaking on apparent tubes (but did not go to intercooler connections, seems difficult to access.
- just cleaned Throttle body with new gasket.
- Checked visibly the spark plugs and wires (they made 70’000 km, but seem to be ok (with Iridium points!)

Maybe I should change also the 2 temp. Sensors on the left and right hand of knock sensor, just to be sure (good idea ? I never changed them so far) are they really temp sensors ?

Anything else I miss to solve the mistery 🧐🧐🧐 specially with my described symptoms ?

Anyway - a great weekend to you all,
Eric 🎩