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Discussion Starter #1 (Edited)
Mazda6i___28k miles____Auto Tranny

Because of a fluctuating RPM problem, I cleaned my MAF sensor about 3 weeks ago. This seemed to smooth out the RPM fluctuation, but the idle seemed too low at stop, around 600 RPM (vibration, stalled once).

I then cleaned my throttle body about 10 days ago according to Mazda TSB # 01-007-09, except I wiped cleaner on the end of the throttle valve shaft, where it joins the inside wall of the throttle body. The TSB emphatically prohibits wiping the shaft in this area (I did this by mistake).

Also, the TSB states:
6. Perform the throttle valve position learning and idling engine rpm inspection.
a. Connect the M-MDS.
b. Turn the ignition to ON without starting the engine for one minute, then turn it to OFF.
c. After one minute has passed, start the engine.
d. Warm up the engine at idling until the cooling fan starts operating or until the coolant temperature
reaches 194 °F (90 °C) or higher.
e. Turn off any electrical load, including the A/C, with the shifter in Neutral or Park position.
f. Let the engine run for five minutes.
g. Measure the engine rpm at idle using the M-MDS to confirm it is within specification according to the
Workshop Manual.
7. Verify repair.


Is the M-MDS only to measure the RPM's or is it also necessary for the throttle valve position learning?

Did I make the throttle body malfunction by wiping the cleaner-soaked rag too close to the valve shaft fitting, making the butterfly valve move erratically?

The bottom line is I now once again have rpm fluctuations, both at deceleration around 35 mph and at stop when I let my foot off the brake (the car wants to lunge forward for about a second). Also at deceleration at around 20 mph, the rpm's do not drop and I can go for perhaps quarter mile without any drop in vehicle speed (no foot on gas). The idle rpm seems high at around 850.

I just had my PCM updated at Mazda dealer with latest software calibrations today, but that did not help.

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