Intake Manifold Removal and PCV hose replacement

[exploring/carolina]

My 2004 ZX3 2.3L Manual Transmission with 110,000 miles, started getting OBD Code 171, one bank too lean & started hearing a hissing sound while the engine is running and for a few seconds after engine shutdown.

Also have a K&N cold air intake system installed for over 100,000 miles without issues.

Found a collapsed & cracked PCV hose behind the intake manifold. Replaced it with a Gates 18423 Toyota heater hose mentioned earlier in this thread. Over one year and 30,000 miles since hose replacement without any issues.

[Allenrox]

Thanks so much for your pics and step dialog. It really helped me with my 2005 2.0 it seems like this was a horrible design but a good exercise in my mechanical prowess! I was able to complete mine in just under 3 hours.

[exploring/carolina]

I believe the OEM PCV oval hose (were failure occurred) was acting like a bellows during each crankcase vent cycle. Also believe the cycling led to premature OEM hose failure. That's why I used the slightly smaller ID round Gates hose for replacement. Just my 2 cents!