p0171 help

[RedGrandprixgt53]

Hey guys I threw a p0171 code and was told that the MAF sensor, vacuum switch valve, and canister switch valve need to be replaced. Im just wondering how do you replace the canister and vacuum switch valve? ive googled it but havent come up with much of anything. unless im calling them by the wrong name. any help would be awesome

[BillBoost37]

Yeah, not quite the names we'd call them. Your best bet before dumping money on all those parts is to head up the top center of the page. You'll see a magnifying glass, click on it.

Search for P0171 and you'll find a lot of suggestions that have worked great to solve the code. A lot a free checks etc.

[RedGrandprixgt53]

but those are the things i know are wrong with it. at least thats what the shop said needed to be replaced.

[01GrandPrixTURBOGT]

It could be a vacuum leak somewhere if your lucky. Spray carb cleaner all round the lines and check your egr valve pipes for cracks. Let me know if you fix it cause I have the same problem on my top swap grand prix and at first it ran fine but now its misfiring and will die at stop lights. If I find out what's wrong with mine ill let you know.

[BillBoost37]

Right, that's what the shop threw at you when they told you that it was a P0171 code. If those other items are bad, typically they throw their own codes. Years of these cars, and putting the gloves on for 3 months straight of non stop P0171 battling....I've learned a few things. Many other guys have found similar or the same things as the cause.

A lot of the items are free to check/look over and maybe solve. A new maf sensor isn't cheap. I'd start by cleaning it, before buying a new one. It's not that often that the MAF is bad. The other items (if you have a 97) would be on the back of the engine, and typically not a cause. The vacuum lines to them could be, as well as other lines.

See where I'm heading with this, if you do some looking around the engine bay, guided by the previous guys that have had that code, you might not need any of the stuff the mechanic was guessing could be the problem.

[RedGrandprixgt53]

yeah i have a 97, and this is weird I was driving the car down the road and the light went off. So I'm gonna take it to emissions while its off to see if it will pass

[GTP in RTP]

The first thing I would do is spray some carb cleaner around the place where the egr tube enters the manifold.
If the idle changes any ,you have cracked EGR tube. Trust me, you cannot see the crack until you remove it.
This fixed mine , with Bill's help. I was pulling my hair out trying everything else.

[RedGrandprixgt53]

okay, ill have too look up a diagram so i can see which tubes are which.

[Scottydoggs]

egr tubes are the fat metal tubes that run from the rear exhaust to the egr, then to the lower manifold its like a flex tube. and can crack, or the seam lest go.


vac routing, egr not in the pic.

[01GrandPrixTURBOGT]

Hey sorry to bring up an old thread just wondering if you found the problem.