Code P0191

That is a fuel pressure circuit problem. check fuel pressure with a gauge auto parts rent it. see picture for other causes.
https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Check it at idle not reving it up it should be in the 40 range all the time if not then it is the pump or regulator soit with a gauge not electrically.

Reading your post said you have a tuner and that may be your problem. The fuel pressure should not go below or down to 10 psi under any condition unless it has been shut off for days. The regulator may be part of fuel pump have the fuel pump driver module checked as the tuner may be messing that up causing your problem.

If you still get the code you may have a wire that has failed, please do a pin to pin check.

Here is a guide to help you.

https://www.2carpros.com/articles/how-to-check-wiring

Let me know what you find

Best, Ken

Good to hear, let us know if you need anything else. Please use 2Carpros anytime.

Best, Ken

Have amechanic check for an abs code to see what is setting it off it will knock off traction as well may be a sensor or rust on sensor. Or a wire broke

Don't know if they work on abs or not a lot don't they just do engine/trans. Check for rust on sensors as they are magnetic or junk around signal wheel if you can see there.