2008 Nissan Altima 2.5L engine cvt transmission

Question

2008 Nissan Altima 2.5L, won't get over 20 mph what's wrong with my car I think it's the throttle position sensor but I'm not sure a now it won't go forward or reverse we just put a new transmission in a few months ago so I know it's not the transmission

Comments

Do you have any engine or transmission codes? there are too many things that could cause the problem.