Why is my truck not running right

What is your question?

Okay hello to whoever is here to help. My 98 dodge ram sport 5.2 liter V8 is running really weird and I took it to O'Riley's and they said it was a bad map sensor so I replaced it but the issue still persists when it's at idle or first gear thru 5th when I give it like a quarter to full throttle it'll act like it's gonna sputter and die and when I let off it'll idle high but the truck runs fine if I give it full throttle when I use any gears but I don't wanna burn gas like crazy can you help? One thing I know too is he replaced the coil pack and the map sensor I replaced was brand new. But the o2 sensor of the exhaust is free hanging under the truck as of now because he cut the exhaust and never fixed it so I don't know if that's the issue someone please help me

What makes this problem better or worse?

When cold or hot it does it the same but idle runs better when I block the valve cover breather hose that goes to the intake

How long has your 1998 Dodge Ram 1500 had this problem?

It's had it since before I bought it