wrong its because lpg has no lubicating properties such as benzine?,nothing to do with the heat it produces .and it is only a problem in older vehichles with cast iron valve seats or set up incorrectly [i.e running to weak, thats why your sierra was slow ,98 octane or 110 octane, lpg will run on a very lean mixture,and to make it cost effective ,you have to run a weakish mixture,but if you want your performance back ,you just increase the fueling on the mapping..................anybody else think theyre clever wimwerf, and as for the experts on cossies ,they have probably never even looked into it as it is still a bit of a grey area,but GM did and raced