So i get this code, only usually after around 100 mile+ trip, wont trigger it unless on a long trip, i have checked for exhaust leaks, and vacuum leaks and found none, fuel pressure checks good, before i buy an 02 could i swap them, to see if i get a p0174 code? then i would know its the sensor before i buy it

 

Yes, swap them side to side and see if the code changes.

 

Thanks!

 

Well code showed up again today, still p0171 so, its not the o2 sensors, the freeze frame data show that it triggers the code, at 569 rpm with the mph at 0 so it shoots it at idle, but i am out of ideas here

 

I would soak the egr valve in some carb cleaner. That's just me though. I do stupid things. I also get lucky some times.

 

Not sure if my 04 has one, but i will take a look, i cleared the code and the next time it started it came right back, so going to have it looked at running lean is never a good thing

 

see if this helps

P0171 Explained - Blazer Forum - Chevy Blazer Forums

 

Now ive got both p0171 and p0174, ive been reading the diagnosing, and checked some of the things will keep trying.

 

Looking at the driver side valve cover towards the rear, i think its the pvc, has come disconnected, ie popped out of the valve cover, i think im going to replace it, and see why it has came out of the cover.