the revs dont go up and down all the time,i spoke to my friend,he has a stage 1 2wd cossie,i told him how much fuel i was using and he said he would get a lot more mpg to me,i dont drive mine hard and neither does he,he reckoned he would get about 75 miles to £10 of fuel,i dont think i would get that.how do you check for a leak at the inlet manifold?