uphill problems
 

so ive been driving the blazer to work lately (now that it is registered), to get a proper feel for its condition. the only thing that i have noticed, other then the tie rods need to be replaced( loose steering) is that when i go uphill it will not hold its speed, it will not go faster then 55 uphill, flats are fine. any idea of what i can do to fix this issue?

also when i hit the gas hard the engine revs high but it doesn't seem to gain alot of forward motion unless i go easy on the gas. the fuel filter has been replaced so IDK..