is this bad?

[my97mitsGSX]

i did a compression check about an hour ago.. when i pulled off the spark plug cover, i noticed a good amount of oil sitting there. I also noticed when i pulled the spark plugs out, that they were black - i guess my car has been running real rich.

when i did a comp test, my compression was

4- 170
3- 160
2- 150
1- 165

the manual says the PSI should be 178 on a new car. My car has about 87000 miles on it now. I know the compression will go down a little, but i think 150 and maybe 160 is a bit too low...

what are my options? and what do i do about running rich?

all i have is a full apexi gt downpipe/exhaust system, bov, and filter w/ piping

 

[Coldandafraid]

well, 135 is the service limit, so you are still above that.

 

[Doug99RS]

There's a bit more to it than just being above the tolerance. If you've got one at 180 and another at 140, then yeah both are "above the tolerance". But you've got 40 psi difference between two or more cylinders.

The tolerances are normally 20 psi variance between any two cylinders. And in this case that's exactly where you're at. You're on the edge of having a really bad situation where the engine brand new.

In older vehicles carbon build up on top of the pistons can cause the situation you have now. The carbon will take up room in the cylinder which will then raise the readings. If you run a search on "Mopar Combustion Chamber Cleaner" or MCCC then you'll be able to find the preferred manor to use it. I think you're gonig to be able to get those numbers lower and closer after you've used the MCCC once or maybe even twice.
Doug