so i did a compression test because my car has been running bad and missing at idle. from, left to right the numbers are, 166, 175, 165, 170. they seem to be ok but, on the first stroke of some of the cylinders, a couple of them seem to hit really low, around 80 or so, and others hit pretty high on the first stoke, around 120/135. they dont really seem to hit very well and the top is usually never the same(tested each 4 times). another thing i noticed was with each test a weird popping sound was made. maybe a sticking or bent valve? does this sound normal and with each test what should i stop at? do i crank it till it just stops rising?

 

piston rings....

 

they are bad?

 

maybe just an idea

 

im not sure its the rings, i have 54xxx miles on it. but what would cause the poping sound?

 

head gasket

 

lol...

 

lol, but seriously when my head gasket went bad i would hear this popping noise after i turned off the car.i would do a leak down test that will tell you better..

 

ill do that

 

good luck

 

thankyou, anyother thoughts?

 

I say check your timing first?

 

Its ok for the compression to slowly climb as the motor cranks. Thats why you let it crank a couple of times. Its the final number that matters. I think that you should be ok...

 

Try the wet compression test to see numbers changes!!!!!!

 

i was going to do that as well, but doesnt that only show bad rings?