So I had the p1259 engine code a couple weeks ago and figured a new solenoid would fix everything, but it turned out to do pretty much nothing. The error code stops my car from accelerating normally, it takes a while to reach second gear, and driving over 65 makes driving car feel as if it’s gonna break down or overheat. It used to stutter and slip gears but that calmed down now unfortunately the code still shows and the little problems still occur. It isn’t the insufficient amount of oil as I make sure it has some every time I drive, and I can’t really figure what else it might be. Anyone have any ideas? Thank you

 

It could also be the oil pressure switch for the solenoid is bad.
I would suggest verifying the wiring to both solenoid and switch are not damaged/correded/disconnected.
If the PCM is not getting a signal then it will set the code, verify wiring is in good order.