DTC PO172 Popped w/ possible suspect [Archive] - GrandAmGT.com Forum

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pkron05
07-13-2007, 03:38 PM
A week ago I started noticing a drop in fuel economy and wrote it off to my excessive acceleration habits. Then I got a SES light, took it to Autozone and it showed a DTC PO172. From the Autozone slip and my GM manual, it states the fuel system for bank 1 was too rich. Remedy #3 of 6 in my manual says to check MAF, vacuum hoses, intake ducting, tb, and air filter for leaks or restrictions. So I looked over my cai for problems.

I didn't find any problems. So started looking over my engine and noticed that the tube (that has ends circled in red) was disconnected (at the end circled in yellow). I connected the tube and noticed it didn't have a rubber sealing gasket/o ring like the intake end did.

So my questions are these: 1. What is that tube? 2. What is the yellow circled area that it connects to? 3. Could the disconnection of said tube cause my too lean condition. 4. Any other ideas for my problem/ solution?

As always thanks in advanced for the help.

lone_wolf025
07-13-2007, 06:24 PM
That's part of the PCV system. The end of the tube on the intake is the part that dumpes the crankcase vapors into the engine. Dunno if that'd do it though...

cardude007617
07-13-2007, 06:27 PM
just out of curiousity, does the sensor and the tube just before the TB have to be in like VERY tight? or can they be in but semi-loose so to speak?

Sprucegagt
07-13-2007, 11:08 PM
Pull the vacuum line off the fuel pressure regulator and see if you can smell fuel. If you can then the regulator has gone bad. Some other things you should have checked are, the EVAP canister to see if it has become saturated and if you have a leaking fuel injector. Does the car run rough at idle?

lone_wolf025
07-13-2007, 11:33 PM
just out of curiousity, does the sensor and the tube just before the TB have to be in like VERY tight? or can they be in but semi-loose so to speak?

The sensor should be snug, just like the tube. Basically you don't want them moving all about and having a noticeable amount of unfiltered air being sucked past them.

cardude007617
07-13-2007, 11:45 PM
well theyre tight but not like air tight i dont know how to explain it

pkron05
07-19-2007, 11:58 AM
*update* after connecting the pcv tube, I checked the EVAP canister, which was fine. Then I took the car back to autozone to clear the code, and everything works fine and car runs good. Must have been that pcv tube. Thanks for the help guys.