UPS delivered my MAF yesterday. I installed it and so far, 65 miles later, the car is running like new. I completely removed the upper and lower air intake boxes and cleaned them with a damp microfiber, then installed a new air filter to protect the new MAF. After resetting adaptations and connecting the new MAF, I measured 1.02 at the MAF with key on engine off which is right on target. I gently blew into the MAF and the voltage would rise in a linear fashion, unlike before where it was erratic and would actually drop sometimes. After starting the car, it measured 1.85 which was still high, but the reading should supposedly be 1.6 on a hot engine (mine was cold). I waited about a minute, during which I watched the voltage drop to 1.70 as the engine warmed up. I did not wait until the engine was fully hot, but I suspect it probably settled at 1.6. In any event, the behavior of this new MAF is totally different from that of the old one, and thankfully it has resolved my flat spot and backfiring. My car now accelerates very smoothly whether I accelerate gradually or quickly.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280