Join Date: Jun 2018
Location: Denver, Colorado
To check for vacuum leak, get some flammable carb cleaner or brake cleaner, or propane works to. Start spraying it around all gaskets and hoses. When the idle revs a little, you found your leak. Alternatively you can use a hose with the water running at a trickle. Same procedure but listen for a drop in idle. As far as checking the coils, you really need a oscilloscope and the ability to know what to look for. Spark plugs usually last 100k. If they are not A/C Delco or Autolite, they might cause a small hesitation under load. Use German Plugs for German Cars, American, Japanese... you get the picture. The wires I would guess are usually a problem on GM V6 engines. They rest on top of the motor, getting hot and vibrating. Anywhere they touch anything including another wire, look for a black spot. Arcing. When the spark jumps out the worn insulation causing a miss. Could be a intake manifold gasket going out as well, these engines are notorious for that. You get fouled plugs. Hope these tips help.