08 xB. 142,500 miles. "Loaned" it to son/DIL for 3 years (son is NOT mechanically savvy). Suddenly developed rough-running - comes n goes - oil consumption up - "misfire" and O2 sensor codes. We retrieved the car, as their local stop-and-rob Toyota dealer quoted "engine-replacement - $10,000" without investigating anything. Thinking it was coil-pack - I asked son to swap 1-2 - now misfire on 1 AND 2 (he did that before we were able to pick it up). Got it home, and compression test found #1 with NO compression at all. Hmmmm, must be stuck valve? Removed rocker cover to check. Intake cam - inner flange at main bearing boss - doesn't look like the exhaust cam. The flange - i.e., a machined part of the cam casting - BROKE OFF from it's position on the cam and wedged-open one of the intake valves in #1 (looks like a big thick "washer" flopping around on the cam). My suspicion is that it was a defective casting. There is nothing preventing "endplay" now, except the timing chain tracking with the tensioner and the exhaust cam sprocket (of course we're not driving it). Anyone ever replace cam(s) without removing engine? I'm up for trying it if I don't have to horse the engine out of there....