My question is based on this statement: "The car feels somewhat slow in general (Low end power has improved noticeably when I found the correct A/F screw position), "

If you don't understand closed loop and how to measure it, you did not find the correct A/F screw position. What you have more likely done is overwhelm the control system and richen the mixture in a compensatory fashion. Basically you are adding to your problem.

The car works properly (fuel control related) when it runs in closed loop. For the most part it can't have a mixture problem if it is in closed loop.

That isn't to say you have a mixture problem, it is just the reason I asked the question.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician