Hello,

I'd like to ask some questions:

1) Can (Snap-on MT2500 + Mercedes module) be used to RETRIEVE and RESET fuel trim adaptation values on a 1994 c220?

2) If that combo cannot be used to RESET fuel trim adaptation values, is there any "hack" method that can be used to reset them without using SDS?

3) Do new MAF replacements (such as those from Fastlane) also use thin-film instead of hot wire as the sensor element? I bought a non-Bosch MAF for my 1994 c220 from Ebay, and it uses a hot wire. It seems to be the constant cause of the DTC P1070 that persists after the MAF replacement.

4) Can long-term fuel trims values that are obtained through OBDII be interpreted as approximate fuel trim adaptation values?

5) After the MAF replacement, the code P0170 keeps coming up every time after I clear it using an ODBII scanner and drive for about 10 minutes. The car runs very well on highway as well as at idle. However, its only symptom is that it often sputters or hesitates for a fraction of a second when I give it gas to accelerate from a stop (usually after exiting a highway and stopping at the red light); it never dies though. This problem only happens when the car has warmed up after driving for about 5 minutes. It does not seem to happen when the engine is still cold. I have checked the fuel pressure regulator, EGR (it has a red dot indicating it was replaced in the past) and made sure there's no vacuum leaks in the engine compartment. BTW, the car's PSE pump is inoperative and I blocked both of its vacuum and pressure lines. I wonder whether this non-working PSE pump may play a role in the aforementioned symptom and DTC P0170?

FYI, I also replaced both pre-cat and post-cat oxygen sensors.

Thanks in advance for all your precious information.

Best regards,

Eric