Surging/bucking at 51k

[AVC]

. Now the problem is FIXED! Much much thanks to all the suggestions.

... lastly battery..

...of all the things that caused the problem it was the Battery.

So a fresh battery completely solved the surging & bucking? What caused you to finally replace the battery? Was it cranking slowly?

 

[yrwei52]

⋯
I did have the fear of a bad batch of fuel considering I moved from CO to CA almost 2 years ago, I always put mid grade Shell in my car but now it’s $1 more a gallon at every station here and so is Techron. That leaves me with Loves or the little mom and pop stations trying to survive and ever changing prices so I’ve switched to mid Loves. (My boyfriend uses Loves also, his ‘12 Mazda 3 2.0 skyactive has no problems and he’s at 98k. No plug issues and he didn’t even replace his till mine was having problems)

You certainly want to use Top Tier detergent gasoline such as Costco gas which is not too expensive in California.

For your 2.5L, no need to use premium grade gas, regular 87 is perfectly fine.

 

[yrwei52]

I might do that in the next few weeks and possibly add in the back diff as well.

Read these threads for more info on ATF drain-and-fill, as well as gear lubricant change on your front transfer case and rear differential:

ATF Drain/Fill

Transmission fluid change without filter replacement

Rear Diff and Transfer Case Fluid Change: Tools, Parts and Links

 

[yrwei52]

After months of no change, the issue did not get worse nor did it get better with the things I had done. Now the problem is FIXED!

⋯ and lastly battery..

I agree with AVC that a new battery is very unlikely to solve your transmission problems if your original battery had no issue to start the engine regularly. One possible explanation is the TCM got reset during the battery change, which may resolve some problems your transmission had experienced.

 

[AVC]

I doubt it was the transmission anyway; bucking and surging are almost always engine related. If it the transmission was doing that, it would have been from significant mechanical or electrical issues, which don't self-heal with a battery reset. The trans would eventually relearn parameters and expose the problem and symptoms again.

I *could* believe that there was an issue with the terminal connections at the battery, or the battery itslef (mechanically loose posts) which caused voltage/current fluctuations, which made the PCM/TCM unhappy. General vibration and engine movement would exacerbate the condition, if that were it. Those connections would have been disturbed and/or remedied at a battery swap.

 

[Kedis82ZE8]

My father had a flakey alternator in an old '93 Isuzu Trooper that caused the AT to buck, slip, and delay shift.

 

[Starbear21]

So a fresh battery completely solved the surging & bucking? What caused you to finally replace the battery? Was it cranking slowly?

Sorry in advance for the lengthy reply...

I had ran out of all other options, I knew it wasn't the alternator because my boyfriends had alternator issues when we first got his mazda 3 and mine was doing none of the things his had done. Dealer also tested and verified it was running fine. I went over every detail of the car and all my issues in the past and remembered back in 2017 when I got caught in a hail storm the body shop killed my battery and told me they replaced it. Well I have a cover on mine so I never took it off to check anything because I was afraid to disconnect the terminals in the wrong order. I had help changing it safely thanks to youtube, when I fully removed the battery and took the cover off the entire underside of the battery and tray had dried acid on it. My battery was leaking from somewhere, none of the terminals are gunky AND it was the original battery from when I bought the car in 2014! The body shop 'replaced' it but the rep at Mazda said it was old and showed me the stamp.

I have since noticed my car starts right away, no drawn out igniting, I all around feel like I have power again. I can climb an on ramp like it used to, no delay in accelerator response I touch the gas and feel it instantly. Dome lights are brighter at night, my shifting in automatic is smooth like butter, manual/sport mode feels more aggressive again if that makes sense. I can crawl steadily uphill into my driveway and not feel like i'm choking it to death. Even my coasting with feet flat on the floor is smooth again. My adaptive headlights are more responsive now, I turned them off when this all started because it was terrible on hard corners at night. No more low idle and rpm drops just sitting at a light.

I'm not aggressive on my baby but I drive it and know that I can remove myself from a dangerous situation on the road if I need to and for a long while I was worried without the power under me to do it.

 

[Starbear21]

You certainly want to use Top Tier detergent gasoline such as Costco gas which is not too expensive in California.

For your 2.5L, no need to use premium grade gas, regular 87 is perfectly fine.

I would like to use Costco but I am more than 45 minutes away from one. I am lucky to have Chevron, Love, Flying J and Shell here. Our base is outside a tourist stop town. Terrible Herbst was just built but it uses chevron at a higher price and the rest are mom and pop gas stations.

 

[AVC]

If the battery was highly sulfated and not filtering the alternator well (i.e old battery), combined with a dodgy terminal connection, the 12v (nominal 13.6v when running) source may have had a fair amount of alternator ripple noise and voltage sag at high current parts, like injector and ignition coil. This can make their actuation/firing weaker and somewhat erratic.

I, for one, can accept that a new battery improved the drivability for the reasons above, and that you've articulated your repairs and the conditions well.