There is nothing unusual about low compression on 1or more cylinders at the
high milage quoted // to run a leak down or air check is quite simple /you
first remove all 4 spark plugs it makes turning the engine over by hand much
easier with no compression // you then  bring up each cylinder up to top dead
center start with #1  go to  # 4 # 3 # 2 turning the crank clock wise to top dead
center of the next #  cylinder // You will insert a air check hose into the
spark plug hole which is sold at most quality parts stores //  it has a coupler
to adapt a quick release from your air compressor hose // spin in the hose into
#  1 it has the same threads as the spark plug ,connect your hose to your air
supply hose before you turn the air on   you will need a air regulator on
your hose set it at appox 40lbs.to start slowly increasing to 50lbs or more 70 to
80 should be max. to hear the leaking area,s  that should be enough to hear
where the problem or problems that are occuring // the air has to go some where
, you have 4 possible area,s  // remove the oil fill cap ,If you can hear air
coming out the fill area the rings are worn , if you hear it coming from the
exhaust pipe the exhaust valve is leaking , if you hear it coming from between
the cylinder and head area the head is loose or the head gasket is cracked //
next remove the air intake boot from the throttle body ,open trottle lever to
full throttle ,if air is coming in that area the intake valve is leaking //
IT can be 1 or all 4 area,s failing    ~~ check closely  AS for worn cam lobes
that will not cause low compression but  it will cause poor performance by not
allowing the valves to totally open  Compression tis created with the valves
closed not open   // The cam lobes are away from the valves when combustion or
compression occurrs ( Worn cam lobes cannot cause low compression )

Don @ DVW Imports ~~ 42 years Parts & Service Exp.
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www.dvwimportautoparts.com