The compression gauge reading should be no less than 100 psi. Check all 4 cylinders and note the readings. The lowest should not be less than 70% of the highest reading.
Running a compression test is pretty much the same for all internal combustion engines.Remove all sparkplugs, marking where the wires went; you don't want to connect the wrong wires to the plugs when you're finished.Start with cylinder 1, screw in a compression gauge where the sparkplug just came out. Some compression gauges just press in, but I prefer the screw in type.Have an assistant engage the starter as though trying to start the engine. Obviously the engine won't start without plugs.You should hear and/or feel the engine compression on the single cylinder with the gauge in place; make sure that cylinder goes through compression cycle at least 3 times.Read the value on the gauge. The gauge should hold the compression reading, allowing you to record the reading.Write down the compression reading and the cylinder number.CLEAR THE COMPRESSION GAUGE. You can release the compression reading, usually by pressing a button or turning a knob. It's different for different style gauges.Repeat the process for all cylinders.Compare the compression value for all cylinders; they should be within a few percent of each other. Any small variance can be attributed to cylinder or valve wear. Large differences indicate severe problems. If any two adjacent cylinders have zero compression, you probably have a blown head gasket.
With a compression gauge. That is the best way. You can guess, but a gauge never fails. http://store.chainsawr.com/
hook avacuum gauge to port vacuum should stay steady if it shakes valve train problem. Do a compression test. When you find the cylinder that has low compression, shoot some oil into the cylinder and take another reading. If the reading changes very little it is probably a bad valve. If the second reading is much more than the first it is probably worn rings.
more that 100 PSI the lowest must be no more that 70 percent of the highest reading
Time for a compression test. Mark the spark plug wires so that you'll know where to put them back. Pull all plugs, screw in a compression gauge and have an assistant crank the engine with the accellerator full open. Let the engine crank until you hear the compression hit the gauge at least 3 times, then stop and look at the pressure reading on the gauge. Record the reading for each gauge. If one or more gauge is significantly below the others, you probably have a burned exhaust valve, the most common cause of low compression in one cylinder.
With a compression gauge.
Remove all spark plugs.Insert compression gauge in cylinder #1Hold throttle open and crank for 5 seconds.Record reading.Repeat on all cylinders.Remove all spark plugs.Insert compression gauge in cylinder #1Hold throttle open and crank for 5 seconds.Record reading.Repeat on all cylinders.
The 1999 Cadillac normal coolant temperature gauge reading should be 180 degrees. A 195 degrees thermostat could be used, causing the temperature gauge to read 195.
Either your oil pressure gauge is reading low , your engine temperature gauge is reading high , or your fuel gauge is reading low so your almost out of gas
gauge is broken