Thanks swoop- I know gas & diesel injectors get cleaned, I just thought there may be a lpg cleaning I wasn't aware of. You are aboslutely correct about the grade of fuel being a factor- this customer refuses to change propane vendors, even after I show them the gunk in the regulator after only 6 months of service. Between the excess tar & the temps these lifts operate at, it's a wonder the propane system lasts as long as it does