• The site migration is complete! Hopefully everything transferred properly from the multiple decades old software we were using before. If you notice any issues please let me know, thanks! Also, I'm still working on things like chatbox, etc so hopefully those will be working in the next week or two.

Can PCM error code P0171 point to easy correction?

J

jlinde

New member
Hi, I am totally new here and I live in Sweden and have a 97 Grand Prix SE 3800. I just bought the car and it
has around 70000 miles on it and the 'service engine soon' shows up now and then - I have a code scanner
and the code is P0171 and I am erasing the code just to not see it but it comes back -it can also disappear by
itself but after driving longer distances. I took a chance and changed the upstream oxysensor but that did not
help at all. I have the shop manual but according to that the reason can be just about anything reading about
P0171. It would be good to have a Tech2 instrument but I do not know if that can pinpoint the fault. Any idea?
Regards, Jan L.
 


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.
 
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
 
jlinde said:
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
Click to expand...

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.
 


You must log in or register to reply here.
Back
Top