Hello, Just found you guys here and hope you can help, I just bought this 2002 propane powered f 150, runs fine on regular gas, but on propane, it seems to idle fine, but no midrange, die's out, if I can get it going, its ok at top speed again?? Any help would be great!! also I would like to change out fue filter, Where is it, and how hard can it be to do?? Oh, this is a FACTORY install,