I have a Devilbiss Air Comp, 5hp, 25 Gal. about 6 yeqrs old with a fair amount of use on it. Has always run well but in the last few days it wont make enough PSI to shut off with no load (off at 120 psi) What do you think, is it worn out or is there something I could look at. I tried removing the air filter to see if that was a problem but it didnt help and there are no signs of air leaks.