Shadetree

97 2.4 auto/overdr. I have check engine lite on for years...dealer says misfire code. Can not find problem. I get poor mileage and when towing with a towbar I get really low power. The miss comes when I try to be conservative with my acceleration...thinking to be easy on the motor and trans. A dealer told me I needed to clean the "gunk" out of the manifold. I just took the fuel rail and injectors out and looked into the holes and they are shiney clean..no gunk. Where would this gunk be found? and how to clean it? Can the oxygen sensors be a problem with the missfire...I am stumped. I found a small rubber hose that went to the underside of the air cleaner case that was rotted open and am replacing it..don't know what it does...it came from a really small metal tube on the passenger side of the engine in the back down low. ??? help.

Will

Possibly needs a fuel filter. Is it possibly plug wires on wrong cylinders? I've just replaced the O2 sensor. But I never detected lost power,just erratic idling