1992 Subaru Justy 1.2 4x4 Help?

i would check the fuel filter it could be getting clogged. take it off and try to blow through it.if the exhaust was restricted all you have to do to check it is have someone rev the engine while you are at the tail pipe and feel the flow and it mite hiss if its clogged.i would not waste your time taking the exhaust apart unless you have to