Hey guys I am wondering can a leak from the intake manifold gasket cause my gs 400 to throw a code of P0171 (Running Lean on bank 1)? I replaced the starter and I didn't replace any of the gaskets because my old ones appeared to be ok.

 

Replacing those starters sure is a pain, isn't it?

The intake gasket is not a reusable part. It should have been replaced, however, it's more likely that a vacuum hose wasn't correctly connect, got cracked in the process, or is otherwise not working right. Running lean bank 1 means that the computer has exceeded it's maximum positive fuel trim for that bank and cannot increase the duty cycle on the injectors anymore, but it's still getting a lean condition from the O2 sensor on that bank. This can happen a number of ways, but most often after work, like i said, it's a vacuum hose not connected.

 

Hey I got a can of carburetor cleaner and sprayed the intake manifold gasket. The car revved up so I am guessing that is where my vacuum leak is coming from.

 

Great! Good that you found the issue, sorry that it had to be that issue. Still, great troubleshooting.