Loss of power when accelerating up hills

[Cojack128]

I have an 1992 fj80 I'm fixing up. Currently it has 250000 miles and runs and drives, but it has very poor acceleration. When going uphill it hovers at about 45mph, if it isn't in decelerating speed.

Couple things that are currently wrong that may be influencing this,

-My alternator may be going out. It charges the battery a little bit but I still I have to jump it with a battery booster everytime I start it. Battery voltage usually hovers around 10-12 when running.
-Map (manifold absolute pressure) sensor is bad and throwing a check engine light.

I plan to fix everything i can but are there any other things that can be influencing the acceleration so much?
Any answers or suggestions would be greatly appreciated.

 

[MGC]

MAP sensor could be the issue so I’d change that first. Lots of things it could be but I’d tackle the usual service items after if not done recently such as air filter and fuel filters. Also check for a vacuum leak