I have a 2000 Ford Ranger and when I either slow down at a stoplight or stop sign it starts to shake. My check engine light was on and it said Cylinder 4 misfire or P304. I replaced the spark plug and then it stopped but then it came back after a month, then I changed the plug wire and it stopped but then it came back, then I changed the coil pack and then it came back. Also when I pick up speed it shakes again but once I get over a certain speed it goes away. I was wondering if anyone knew of any other solutions on how to get it fixed so it stops shaking cause it is annoying.

 

It's the fuel injector sticking.