So a little history.
I have a 2001 4-door Jimmy, just replaced the cats and the O2 sensors are reading correct on the scope, BUT it only idles fine with the MAF unplugged.

Plug the MAF in and it idles low and eventually stalls; unplug the MAF, and it runs absolutely perfect (new Delphi MAF BTW)

Anybody have any ideas or help please?

Thank you in advance.

 

What is your MAF reading at idle (and please specify idle speed)

 

Good question, I never took any.
Task for tomorrow=take MAF readings.

 

Is it installed the correct way? Have to ask because I have seen them installed backwards on a few vehicles.

 

Finally got a break in the constant rain and other projects to get the readings.
The MAFreadings are inconsistent (see pics) and now I'm getting two codes (see pic)

 

First MAF reading is way out low.
Second is OK
Third and Fourth are marginally low.

But better fix the O2 sensor codes before worrying about these. Diagnostic charts are attached. Whatever it is, it is affecting both O2 sensors. Check fuse 5 in Instrument panel fuse block. Also be sure to study the attachments including description, wiring diagram, and diagnostic aids. Also you can watch the O2 sensor voltage with KeyOnEngineOff and tell some things.

 

Thank you Lesmyer