I need some advice. I started having a difficult time keeping my 02 F150 with 4.6L Triton running under 1000 RPM and occassional weird surging. It was throwing Lean and O2 Sensor codes (sensor has been out for a long time). My local shop ran a compression test:

1 = 185
2 = 165
3 = 130
4 = 175
5 = 170
6 = 160
7 = 145
8 = 140

They are telling me that I have one or more cylinders tanking and no good options. Does this sound right? If the 50lb difference is the red flag then I assume valve and/or rings. Does no one do valve and ring jobs any more? I'm getting the impression that replacement is the only real option.

Engine is developing good power and seems to be running fine other than low idle but under 1000 it is knocking and missing and just not running well at all. Engine has 185,000 on it

Thanks!

Mark