last week just noticed performance on petrol was very poor. (i have lpg) well after thinking it out i sort of worked out it was fuel pressure, so i automaticly changed the fuel filter with was in fact blocked. how ever the problem is still there, is it my fuel pump, or bloked lines. the car idels ok, but when i give it some revs it leans out. the power comes and gose during heavy accleleration. i don't think it is the fuel pump, because i was under the impresion that the fuel pump either works or dosen't