UnZFeat'd

iTrader: (1)

I had a bunch of problems the other day and i checked my o2 sensor and it was completely grinded off. So i tried changing wires around and it was throwing a p0300 code. So i checked the compression and cylinder 5 is giving me like 10 psi. Checked it against cylinder 3, which is giving me 125psi. What should i start checking? Also, when we cranked it, some crap shot out of the spark plug hole and and i saw an oily substance on the compression tester. If that is any indication. Thanks

joecar

Do you have a pic of the O2 sensor...?

Do you have a pic of the spark plug from #5...?

Which position is that O2, is it driver side upstream of cat...?

89 formula350

iTrader: (8)

you can put a table spoon of oil in the cylinder and see if the comp goes up. if not take the rocker arms off and perform a cylinder leak test to see where the comp. loss is