anyone every notice this, it has just developed in my car. when I let all the way off the gas and teh revs come down, at a certain point, it stumbles like crazy.

 

Ive had mine for over a year, and havent had it happen yet. Is it a really bad stumble, or just some backfiring.

You should be getting relatively no fuel to the engine when you take your foot off the gas, and your injector duty should be at 0.0%.

The only time that mine will stuble is if I forget to take it out of gear as I am coming to a stop and the RPMs are around 1000 to 700, right before the engine dies or stalls cause I forgot to take it out of gear. oops.

 

it is had to desccribe, it is basically not stumble but a drastic change in the rate of deccelraion. If I am at say 5k rpm, let of the gas, at about 3k, it will now drop much, much faster than from 5kl to 3k. It is a noticable drop bnot gradualk liek it shoudl be. Feel like one big stumble. no back firing

 

Page F-133 dashpot adjustment in the Mazda manual.

Page 33 deceleraration adjustment in the Commander manual.
Set to at leaste 200 above idle. Try even higher if needed.

Try them.

 

I get a stumble when I let off the gas at lower speeds in 5th and some times 4th. For instance, I'm on a 45 mph road and I see a stop light has just turned yellow (maybe 1/8 mile ahead) If I let up on the gas slowly i will decelerate normally, but if I just lift off the gas real quick at these slower speeds and higher gear combo the engine will buck or stumble. from higher speed let offs or if I down shift to a lower gear like 3rd.

That is my only experience with stumbling.

 

I adjusted my dashpot back out and it fixed the problem, I had moved t far forward, not by specs in manual, just by eye balling it. I think my dashpot may be shot, the tip only pertrudes maybe 5mm. Is that normal, I have nothing to compare it to.