Tune up or transmission

I have changed fluids, plugs, wires and my truck still drives like it’s stuck in 2nd gear and dumps gas like it’s free!!! HELP!!!

Tell us what make model and year. How long has it done it. Did it happen all at once or over time? How long have you owned the car?

From what you have written there is just too little to go on.

Maybe it IS stuck in second gear! Move the transmission shift lever and check each detent on the transmission. The repair manual helps awfully in this.