a burnt valve looks like a wide crack in a valves' head. when a motor runs too lean, the cylinders heat up too much, causing the head of the valve to heat up faster than it can dissipate the heat, causing the valves' head to crack. once the valves' head starts cracking or melting away, you lose compression in that cylinder, and the engin will vibrate and it may not idle at all.
Sounds like a burnt valve, the gas is not burning because of no compression due to burnt valve and gas is pushed out of exhaust unburned
You can have a compression test done on the engine to determine the condition of the rings and valves.
You take the car to the Shop, pay someone 1600$ (est) to remove the cylinder head and get the head rebuilt. Have them replaced the water pump and the timing belt while they are doing it. The reason a valve gets burnt, is that the valve does not touch the valve seat to enable it to be cooled. Aka a valve lash adjustment problem, or a Bent valve
Remove the head and have the valve reseated or replaced.
A compression test will show you if you have a burned valve.
A compression test will show you if you have a burned valve.
Exhaust coming out of the airfilter indicates a possibility of a few things. Motor has jumped time. Burnt Intake Valve It can also be that the valve lash is out of adjustment.
Oil leak Burnt oil smell as oil spills on hot engine
buy a new valve
Backfiring in any motor is either badly out of time or a burnt valve.
check for bent or burnt valve check for bent or burnt valve
If you mean the motor is burnt then the answer is no. It is not cost effective.