OK so I bought this 1992 olds 88 for $200cdn. I fixed the passkeyII prob for $50 cdn, fixed the whining alternator, got it running on synthetic oil , got an aftermarket 2 stage foam filter, threw in a can of fuel injector cleaner, new plugs and wires, but my fuel economy is still bad. Im getting 350km(210Mi) to the tank on 91 octane. What do I do now? should I get the fuel injectors cleaned by my mechanic?... I am putting in a new fuel filter this week, but I dont think it will do too much. Maybe my engine is gonna go soon. I have 300,000km(180,000mi).