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99 Dodge Ram 1500 Automatic 5.2L

Ok here’s the issue. Whenever I come up to even a slight hill the A/C will stop blowing and the vehicle speed will drop 3-5 mph and stay until after the top of the hill and will be sluggish to regain speed and A/C will blow again once original speed is achieved. No engine light or warning lights come on. What could be causing this problem?

Chrysler engineers favor giving you maximum power to pass or go up a hill over a/c so they cut out the a/c under low vacuum conditions. The more you open the throttle, the lower the vacuum. If it is happening too early it may be a sign of an engine problem.
It may be a misfire under load or a vacuum leak.
How old are your plugs?

I have no idea how old they are. I am the second owner of this vehicle so I could ask the original owner if he had the plugs replaced at any time. Also it takes its sweet time to get back up to speed and I also think it runs sluggish in general. Whenever I put hard acceleration the truck doesn’t seem to pick up speed as fast as it should. Maybe it could be the tranny? It doesn’t slip or anything, it just doesn’t seem to have much push to it.

Wouldnt a vacuum leak or misfire come up on the engine light?

This is usually caused by a vacuum leak in the supply to the HVAC controls. The first place to look is at the vacuum lines to the cruise control servo under the battery. Battery acid can damage the plastic vacuum lines. Next test the vacuum check valve to the firewall/HVAC system.

You might try replacing the fuel filter (it’s probably under the truck, mounted along the frame) to address the power loss…Mileage on truck?

You need to replace the plugs and wires if you have no idea of their condition.