Excessive downshifting in 2011 Buick Lacrosse

[GerGa]

hard to say if this is even a trans issue. It could be a trans issue, or the engine could just be down on power and the programming making it seem like to you, the driver, that it’s a transmission issue. How many miles on this transmission fluid?

Without doing maintenance to get the whole thing up to date, you may be chasing ghosts. Air filter, plugs, oil, transmission fluid…possibly plug wires. Note - bad plugs or wires are most prone to cause problems when loaded up at lower rpms. Revving higher is easier for the spark to push through (less dense air).

As far as trans fluid, see first post for more details, it was rebuilt.
Thanks for the input none the less.

 

[Marcozi]

Scan the engine computer and automatic transmission controller for codes. That is always the first step.

 

[GerGa]

Scan the engine computer and automatic transmission controller for codes. That is always the first step.

Well the trans shop said no trans codes. It's been a couple years since it first happened so my memory is fuzzy, but I probably scanned for transmission codes with my Tech ii when it happened again.

 

[Bladecutter]

112k miles?
Have you cleaned the MAF sensor recently?
Maybe its not a fuel issue as much as it is an issue with it measuring how much air is being ingested when you are trying to accelerate.

Might be worth picking up a used MAF from a salvage yard with less miles on it for a cheap test.

 

[Stimp]

This video shows the plugs being done. Requires taking the intake off, doesn't look that bad.

It's not as bad as it looks.

Make sure you clean up the PCV from the rear bank and drill out/enlarge the holes in the PCV. There are numerous instructions for that out there.

 

[Figure It Out]

I had a Grand Caravan 3.6 that did that.
The only fix was to unplug the oil pressure sensor that was under the intake manifold on the 3.6.
It turned on the "check engine" light but did not affect running.
Shifted fine after that.
I was pulling my hair out until I got that figured out.
There is probably some unneeded sensor causing it that you can just unplug somewhere.
It could be a faulty MAF sensor though, too................. had that happen.