1998 Pontiac Grand AM GT, P0171

This 1998 Pontiac Grand Am Gt with a 3.1 Liter V6 came in with a surging idle and service engine soon light on. I checked codes and found a code P0171 stored for Fuel Trim System Lean. Sounds like a vacuum leak to me. I tested with propane and found that by adding fuel near the pcv valve hose tee, at the throttle body, that the idle would smooth out.

I removed the two top screws for the throttle cable bracket.

Then loosened the hose clamps and removed the intake flex tube.

Now I could access the lower nut that was still holding the bracket in place.

I then went to the rear of the engine and removed the harness connector shown below so that I could gain access to the other end of the tube assembly.

I installed the new tube after cleaning the goo (technical term) out of the hole in the throttle body. Connected the hose at the rear of the engine, installed the pcv valve and installed all previously removed items.

I think you can see the difference between the grommet on the old hose tee and the new one.

4 discussions on “1998 Pontiac Grand AM GT, P0171”

  1. Thank you Sparky! Your tip on using the carb cleaner to find the vac leak worked great. My 2005 Buick with the same type problem. Turned out that the previous mechanic left the throttle assembly bolt loose by 1/2 inch after he replaced a defective fuel rail valve. I found the problem and had it fixed in 5 minutes thanks to you!

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