I have a 1995 2.5L 5 speed and I have a big problem with it. When I push on the gas it only goes up to 2000-2100 rpms. The car runs but really slow.When it reaches 2000 rpms it goes down to like 1200 rpms or less and it keeps doing that. I checked the fuel pump and it is good. I replaced the fuel filter but I still have the same problem. One time when I was pushing on the gas it went up to 3000rpms but it only happened one time. Any Ideas what the problem is?