stumble and stall

[HAMP]

I have a 190e 1986 Mercedes Benz.

My problem is car will idle but the economy gauge will be sitting at 50%. I can barely touch the gas pedal and it will stall out.

This problem really varies, it started out as not being able to drive past 40 mph, as I test more the mph will get lower and lower.

I first guessed it may have been the fuel filter, bought a new one and the car drove normal for 1 day, then the speed went back down to 40mph then down to 2mph with the gas pedal pressed all the way to the floor.

Now it sits in the driveway and when I go to try to figure things out, sometimes I can press the gas pedal and it barley stays running or it will stall.