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Mazda5 Engine Stumble Service Bulletin
The most dramatic symptom this SB addresses has for us been a very rare one, but a very noticeable and annoying one when it does happen. This was, approx 1/2 second after applying pressure to the gas pedal from a state of coasting, in the 1500-2500 rmp range, getting one (only one) sudden, brief, complete loss of power. This was felt as a big jerk, something all passengers would notice. The power loss would always be over with in a split second and the engine would begin to pull normally. I have no experience with automatic transmission 5s but I would guess that if the same symptom were to occur it would be more damped out by the torque converter and possibly more subtle.
So far so good on the new SB stopping the above obnoxious behavior -- but it will be months before I'm really convinced it's totally gone.
However, I think there's another much more frequent, much more subtle behavior that is also affected by the SB in a good way. I always used to think our 5 had poor throttle response compared to our other car, and Acura Integra. I don't mean absolute amount of power -- I mean instantaneousness of response to small applications of throttle. The Integra's engine always responds immediately, no waiting, to a nudge of the pedal. The Mazda always seemed to hesitate for a split second before starting to pull. I am pretty sure this has now changed for the better with the SB and I like it a lot.
It's important to note the date of the SB -- the solution to the problem was not invented until 6 weeks ago. I've been trying to complain to Mazda since almost Day One when we bought our car in March 2006. The first dealer service call that year produced no effective result at all. They didn't know what I was talking about and I don't think they did anything to the car except check it over. Then last year sometime we tried again, and at that time there had been published an official Mazda Service Bulletin (not the same one as the one I cite above), and we got a download of new PCM ("Power Control Module"? I think??) software. This fix in 2007 was an improvement but did not make the problem totally go away.
Being a compulsive and geeky car nut, I had all along been hoping to hear more scuttlebutt, and I finally struck paydirt last week at the Kirkland WA Mazda dealer (not my regular service spot). Although the Service Advisor did not have any new knowledge at first, I was persistent enough and he was patient enough, that he finally discovered that SB 01-008/08 now exists. I had the work done at Everett (WA) Mazda day before yesterday, and once I was able to cite the SB # they were totally ready and it was easy. (The work allocation time is only 20 minutes to do the new software download).
Anyway, my recommendation is to do this SB on your 2006-07 Mazda5, whether or not you realize your car has the symptoms I described here, or not, and whether or not you've tried complaining prior to Feb 2008 or not. The software engineers in Hiroshima (or wherever) have been at work and have something good for you. You'll like the feel you get -- and what the heck, I bet it even improves gas mileage (but I can't say it's any more than 0.01 mpg).