My 85 300TD Turbo is prety slow. I have adjusted valve lash, checked timming chain strech (about 2 degrees), checked Inj timming (drip method about 24 degrees BTDC), the alda is maxed out with little or no smoke. I put a boost gauge on it and there was only 8psi, so a took the hose off the waste-gate. The boost went to 12psi. It seems like it should be more? I live at 8000ft above sea level and need the power in the mountains. Also I am only getting about 20mpg. Can anyone help?