hi all, I have been irritated by a po171 - lean condition bank 1. I have done a propane test and carb spray test and there are no leaks that I can find. I did notice the little plug from the oil dipstick was missing the part in the centre - I noticed this after the tests so my question is, will the missing plug cause a vacuum leak? I thought the case was under positive pressure and not negative. wont the missing plug cause both banks to throw a code?

it is vacuum leak cause fuel trims are high at idle and then get close to 0 with acceleration. the idle is a bit rough but no other issues I can think of.

thanks.......

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

Read this https://www.facebook.com/GM3800Tips/posts/551818071634026
...especially item 7

This is also assuming a properly functioning and sealed PCV valve.

Missing/ failed o-ring/pcv valve can also allow crankcase vacuum.

_________________
~Randall~


1993 Buick Park Avenue - 197k - Some odds and ends done - Simply won't die
1994 Buick Regal - 78k - Bone stock - Always ready for a good kicking
1990 Oldsmobile 88 - Gone to a better place

OK, THANKS........

_________________
poverty forces one to do unorthodox things

2000 SSEi
past rides:
1996 SSEi
1992 GTP
1987 Grand Am

This. Plus replace PCV with NAPA, Standard Ignition, or Delco. Lots of cheap valves around that don't flow the correct amount of air.