Thread: Can PCM error code P0171 point to easy correction?

google would be your new bets friend P0171 - Google Search

start with some carb cleaner, or intake cleaner, and spray around the engines vac lines, if the idle jumps up when spraying, you found the vac leak, the rubber T's like to break, they get dry and brittle over time. if you get nothing, try moving the vac lines a bit while spraying, also spray around the throttle bodys gasket and vac lines as well.

You more than likely have a vacuum leak which is very common and causes the P0171 error code. Make sure you take a look at the EGR valve, there are 2 metal lines attached to the valve. One goes to the rear exhaust manifold and the other goes to the intake manifold. Take the metal line/tube off that connects the EGR valve to the intake manifold and inspect the tube for hairline cracks. This is very common and I've seen it on numerous grand prixs. Also if your still running the stock intake manifold gaskets, you might want to consider replacing them anyways being they are quite old.

You want the metal ones.

Originally Posted by jlinde

I will check the mentioned hoses and tubes -the changing of intake gaskets sounds like a very good idea as there is a slight
smell of antifreeze now and then. I changed head and intake gaskets on my doughters 3.4 liter Montana and on our 94 Pontiac
Trans Sport but for the 97 3800 Grand Prix there are 2 different types according to Rockauto so maybe I have to buy both types
or wait until the intake is off. /Thanks, Jan L

My 97 has the ones will the dowel alignment pins but some 97's dont have this. These dowel pins help prevent the gaskets from slipping when installing the manifold. It's up to you, but make sure you buy the aluminum AC delco intake manifold gaskets. The quality of these gaskets are so much better. My 97 gtp I purchased with 34k miles in 2004 or so and the stock gaskets were cracked horribly. Make sure the gasket area is nice and clean before installing new gaskets, also don't forget you MUST apply a gasket maker (I use GM assembly adhesive) to the bottom corners where bottom gasket ends meet. If you don't do this, you WILL DEVELOPE a vacuum leak.