tested compression due to going crazy chasing codes. Cyl 1 has 85 lbs, #3 has 90lbs...others 115-120.
should i just get valve job or total rebuild? 90,000 miles on the ol' blazer. OR...?????????

 

All spark plugs should be removed, fuel pump disabled and the throttle propped wide open during the entire compression check. Watch compression gauge pulse 4 times for each cylinder, then take reading. After checking all cylinders, squirt approximately 1 tablespoon of oil in each cylinder just prior to checking each cylinder again. The first test is a "dry" test, the second is a "wet" test. If there is a substantial difference between dry and wet readings, suspect poor sealing piston rings. If the readings are similar, suspect a leaky valve. You need to do both tests to determine what the problem is.

 

I'm not an up to date mechanic.....70 years old and looking to the younger set for help....SO...I just gotta TRUST the mechanic. Cyls 1&3 are mis-firing, low compression in these two. Just don't know whether to throw money into it, or dump it. Don't want to chase more problems. It served me well, had some fun off road out here in Utah, but didn't beat it..............NUTZ..........