Show of proper steps to use a vacuum gauge diagnostic how to use a vacuum gauge properly to solve almost anything car or auto mechanical problems solved even head gasket leaks or egr emission because a expensive tool to find exhaust clogged or air filter even intake manifold clogged or restricted same with exhaust restrictions then check your pcv system positive crank case ventilation also break booster we can go even further your truck idle problem down to ignition coil or even wires coil pack then check your timing adjustment or distributer advance timing retarded timing also check your valve lash valve clearance valve adjustment diagnostics for compression detailed so you know if its worn piston rings or sticking valves ac air conditioner comes on youll see on the gauge overheating cold engine bad fuel check spark plugs fuel filter check this gauge was everything before obd2 car wont start how to diagnose a no start faulty fuel injectors you will be pointed in the right direction i will do a series as you can see there no start or no diagnostics vacuum gauge cant perform as the how to fix egr valve restriction or even how to on egr vacuum leak how to blow by pcv included in the series or even how maf sensor and how to map sensor so you no where to start even electrical trouble shooting youtube trending topic could easily be vacuum diagnostics included will be how to trouble shoot caulty fuel pump how to bad injectors how to emissions code how to emissions test in the series so be patient this will take time how to tell if a car is bad how to know if a engine is bad