Mitsubishi Repair: compression follow up, psi readings, head gasket

Question
hi again! i'm writing you back to see what you think about these results. i checked the ecm and the capicators are fine. got spark and fuel #2cylinder still not getting it. compression check yesterday all cylinders are at 135 +or- a few psi but the #2 is at 23psi........i put a little oil in the cylinder to see if the compression would raise and it did but only to 30psi. the manual said if it doesn't raise "signifigantly" then it is leaking past the valves or the head gasket. is a 7psi increase a "signifigant" increase? what do you think it is. i believe i need to rebuild the head. possibly the valve seats or guides are worn or maybe the head gasket is giving out.......any suggestions would be greatly appreciated!!! thanks!
p.s. do u think i may have a ton of carbon build up or dirty valves. i think the person i bought the car off of was running 86 octane in it when it only takes premium i know that means dirty valves. just a thought.

Answer
Ramon,
The 135 psi readings are within the limits (Standard being 164, and minimum being 121).  The 7 psi increase you got in #2 after adding oil is not signifigant.  Your problem is most likely a warped head gasket, or possibly a worn piston ring.  Your cylinder head should be fine, but since you have to remove it anyway to replace the head gasket, you might as well have the head rebuilt.  This site offers head rebuilds for a decent price and lots of experience: http://www.taboospeedshop.com/

Running 86 octane is definitely not recommended, as you know.  It will not cause too many problems, but it can wear down your knock sensor.  But if you get your head rebuilt, your valves will be fully cleaned.  Continue to use 91 or higher octane in your car, and every oil change, use a bottle of STP Completet Fuel System Cleaner.  That should ensure clean valves and fuel passages.
Good luck!