I was driving down a road with a slight(very very slight) incline, the car was doing about 50 at 1800 to 2000 RPM when it started jumping and dropping rpm like a misfire. I have recently changed plugs, wire, all three coil packs and fuel filter. Please give me your input. all post will be taken into account.

 

What's the ride?

That is a shifting point to go into 4th gear, up an incline it can hold the transmission and act funky. Next time it happens, just ease off the gas for a second, then step on it again and it will downshift and make it up the hill no problem.

It's common with these cars. A good tune for transmission line pressure and shift points would fix that. But it's nothing wrong.

 

Cruise control will also cause it to act funny if it's trying to coast at the set speed, annoying enough that I take it off.

 

it is a 98 Monte Carlo LS. Well I'm sure the tranny fluid needs changing
thanks for the input