test was done on a 2000 Chrysler 300m with 405,000. i got a misfire engine code p0305, misfire on cylinder #5. swapped out ignition coil pack and spark plug for cylinder #5 w/another cylinder but error code returned/no change for cylinder #5, this rules out spark for the misfire code.
using water and propane i found a vacuum leak under the intake manifold for the #5 cylinder.
code was retrieved using elm and android torque app. gasket needed is Fel-Pro Ms 91990 Plenum Gasket Set

 

Break cleaner or carb cleaner does the same thing

 

yes but not as safe. those are flammable liquids that will/can catch on fire if theres a ignition source or spark nearby. propane gas will just do a quick burnoff

 

its a vacuum leak it sucks air into the intake then burns it then it goes out the exhaust. You have a stronger change of hyrdolocking the engine with all that water you put near the intake. If the leak was big enough and it sucked all that water in it would lock that motor up like driving through a puddle of water would.

 

u should checkout scannerdanner videos, he seems not to worried, but agreed, propane is the way to go