V6 LS shuts off when stopped, noob taking on replacing PCV

[Keaze]

Alright so mine is 2000 LS V6

Just replaced the alternator, car stalls in park or when stopped for an extended period. Turns over no problem and has not given me any problems while moving/driving.

The OBD2 codes I'm getting are P0156, P0401, P0171, and P0174. One of these codes made me believe it was the EGR so I replaced it, still getting the code. I checked the forums and referred to the maintenance manual which says replace PCV at 100k. It makes sense to me that it can be the PCV, after checking out my PCV hose it's pretty ghetto, so I am definitely replacing that. However I am afraid it is the PCV elbow as well which connects beneath the manifold so I can't immediately tell.

So I come to you guys for help. If it is likely that the vacuum leak is the PCV I should replace the hose, the elbow and the valve, correct? Also some people say they use their old gaskets for the intake manifold when reconstructing. Shouldn't I replace those too? While I'm taking **** apart I figured I should change plugs and coils but I just want to make sure there isn't anything I am overlooking and that I am correctly informed when approaching this.

 

[joegr]

Sounds good, but you really should post the five-character OBD2 code(s) that you have. There in no code that absolutely says replace EGR.

 

[Keaze]

Sounds good, but you really should post the five-character OBD2 code(s) that you have. There in no code that absolutely says replace EGR.

Thanks, just added the codes.

 

[joegr]

P0156 Could be a bad O2 monitor (post cat, driver's side), or it could be wiring. You could swap the two monitors around to see.
P0401 is very likely caused by the EGR exhaust passages being clogged/restricted.
P0171 + P0174 could very well be an intake or PCV leak.