So i have this car that when i want to speed up, the rpms will drop just below 2000 and stick there no matter how much i move the throttle, unless i floor it or let off the gas and press it again. This is happening in all gears and does it about 70% of the time. It will run kinda rough and gas pedal will pulse. Fuel filter was just changed.

Do you have any service soon/check engine lights on? If so..
The car may could have issues with the throttle position sensor or MAF.
Try disconnecting the MAF and see how it does.
Look for any broken or cracks /leaks in vacuum lines, throttle body bore cleanliness, and correct movement open/close of throttle plate.
Have you done a tune up with new air filter/ spark plugs and wires lately?

Have the car scanned for diagnostic trouble codes. Autozone will do that for free. You could be getting a misfire, there could be an issue with the throttle position sensor, the fuel pump could be failing.

Does it idle rough?

Do as the guys suggested....also check back pressure...

Already tried the maf sensor, car ran horrible. Throttle body is clean i already tried spraying some cleaner at it. And i had recently done new spark plugs and air filter looks like it just came out of the box. my car was doing this before i had touched anything on the engine. But I'll check vacuum lines and the fuel pressure