I have a 91 classic with the 3.9 and a couple days ago i got in it and realized that when i push down the throttle nothing happens. The engine doesnt rev up to higher rpms and when i hold it to the floor it loses more power and sounds like its going to stall. Its not even going higher that 15 mph down the road and 5 uphill. I've replaced the fuel filter, checked for kinked fuel lines, replaced and cleaned vacuum lines and still its doing the same thing. three months ago ive replaced the plugs, wires, exhaust maifold gaskets and done a regular tune up so i dont know what it could possibly be. I sounds like the engine is clogged and is not getting any fuel so im not sure if its the TPS or the fuel regulator. Has anyone had this problem and got it going again?