also in the "chassis" section of DIS fault code "5F23 DSC: Engine management: interface" came up

Hmm.... what's the date on your battery and how do the terminals look?

new battery last year, terminals are clean and snug

Bumping my old thread...

I took it in to my local Indy. He wasn’t able to find anything conclusive. He said there were no vacuum leaks and everything else looks fresh (spark plugs / coil packs). He said to run some fuel system cleaner to clean the fuel injectors, and that might help. He didn’t charge me anything for looking at it and told me to drive around for a while to see if it improves with the suggestions.

I ran fuel injector cleaner with no improvement. I replaced the fuel filter and it ran better for a couple months, I thought the problem was fixed. But the vibration issue has slowly started coming back.

I noticed it is worse in the morning when the engine is still cold. Once the engine warms up it improves a little, but the vibration is still there if I suddenly accelerate.

No codes present

Took it to another Indy. They checked the suspension, transmission, driveline, and differentials. Everything looked good. The only thing they noticed was some "NAPA" front axles. They said they do not recommend using any aftermarket parts and suspect that that is the vibration problem I am having on acceleration.
They quoted me $2400 to replace the front axles with OEM parts.. Anyone else think that is outrageous? They also said they cannot guarantee that replacing the axles will fix the problem that I am having.

ordered new axles, will replace them myself. I went with Brand new OEM axle shaft assembly from GKN Loebro. They go for about 300 each.hopefully that will fix the issue I am having.

Itscoo2pyopants, did you resolve the issues you had?