Welcome to the forum.
Lack of power would have me checking air filter
Timing light to check for bad plug wire or just replace them
Distributor cap, may have gotten wet
In neutral/park can you get it to rev up with out any kind of issue?
Possible weak or bad fuel pump or filter
Like said before it would help to get your profile set up too.
98 TJ, 5 speed, Dana 30 and super 35, 4.88 gears, Detroit in rear, ARB front, 33" tires, 4" procomp lift, smitty front fenders, rock sliders and armor, XRC 10K winch, custom bumpers, Atlas II 5.0:1