help narrowing down problem

[zinch]

i'm looking at picking up a 91 240sx as a DD, and found one that needs some work.. i'm alright with repairing, however, i'm not so good diagnosing.. supposedly the only problem with the car is that it's running about a 40 compression.. are they just doing the test wrong, or is this a symptom of something fixable?

mike

[S3t0_S13]

searchsounds like a number of things wrong...who are they?how are they doing the test

could be a headgasket, etc....