Nissan Repair: nissan repair, compression gauge, nissan repair

Question
i have a 97 altima and the air coming out my tell pipe is pud pud pud like air is not coming out i change maf,spark plugs, wire,knock sensor and still have pud pud sound.

Answer
Cornell,

You will need to perform a compression test since it sounds as if you have a burnt exhaust valve.  Pull all the plugs and get a compression gauge and then you will screw it into one cylinder at a time and turn the engine over until the gauge reaches maximum on the dial.  Then, do the next hole until you are done.  Compare the numbers and the low one will be where you have an issue with compression.  Now, put a tablespoon of oil in the low reading cylinder and recheck the compression.  If the compression comes up it is the rings that are bad and if the compression does not rise from the original reading it will mean a burnt valve.  If the valve is burnt that will mean that it is leaking compression and you will need to remove the head and have the valves machined and the one that is burnt replaced.