engine codes 171b 172b 174b 175b

i have an 01 passport 4wd 97000 miles. I am getting these codes and it idles rough at stop signs sometimes. It also dies when i start it sometimes. I had the plugs replaced with recommeded plugs from this forum and egr cleaned in past summer. Any bullitens on these codes all together?

i bet you have a blown intake manifold gasket. i just changed one that was dying on me while idling and stopped in traffic. i was showing codes for lean, rich, random misfire, and o2 sensors. all fixed by changing intake gasket, then i traded the car.

i hope its not the intake gasket. i know these are o2 sensor codes. I found some at napa for 54.95ea. i dont want to just go replacing parts

you will get o2 sensor codes, because all the air the engine is getting is coming through them. can you hear a sound of air sucking or whistling under the hood.

btw- intake gasket = 39.95 advance auto or auto zone

it is definitely the intake gasket on the drivers side. I got the parts today, along with new antifreeze, oil, filter. I dropped it off to my mechanic today. I didnt even ask a price. I just need it done. Does anyone know about how many hours it takes to do this?

i did mine in about 3 hours or so.

You might provide your mechanic with the correct torque specs if it's not too late. When you pick it up, pop the hood right away and listen for the telltale whistle of a leak.

i found the torque specs on this site. i think it was changed to 13 from 17 is this correct.

Only info I can give you is that there's a TSB (technical service bulletin) on all 1998 to 2003 Isuzu models equipped with 3.2L or 3.5L engine that revamps the torque specifications for the "gasket intake manifold to cylinder head". Revised torque for both the 3.2L and the 3.5L is 13 lb ft.

Other specs:

Intake Manifold Fasteners: 16 ft. lb.
Common Chamber Fasteners: 18 ft. lb.
Throttle Body Fasteners: 18 ft. lb.

img replacment is a 1 hr job if the person doing it knows what to do

picked it up today and everything went well. Got the parts at local auto shop for $39.95 and mechanic charged $120 to do the job. no codes and no air leak. Hopefully it stays that way!