Re: Lpg Focus Misses And Backfires
90% of the time when a car backfires only on LPG it means it's running too lean. The checks you need to do depend on what kind of system you have. Some are adjustable just like a carby, some are computer-controlled and not adjustable. Start with the basics. Check that the air filter element is not damaged, that the intake pipes are not split or have missing rubber plugs, check that the spark plugs aren't worn or that the gap does not exceed 0.9mm and also check for carbon build up inside the mixer at the throttle body and gum build up inside the LPG converter and jets.
Whatever you do, if you can't fix it yourself have someone look at it. Remember that Focus have a plastic intake manifold that could get damaged if a backfire is serious enough, not to mention the O2 sensor and the catalytic converter. cheers