172 ignoring lambda ??

[Ex-User (107751)]

Unplugged post cat lambda , no lights on dash. Unplugged pre cat, still no lights , and the car runs exactly the same !
I used to get the post cat lambda fault code with my scanner because of my decat. 2 months ago I stopped getting that fault code, and my fuel economy improved noticeably. Maybe it ignores both lambdas since then for some reason ?

 

[bloke]

what did live data show? was car up to temp?

 

[Ex-User (107751)]

unsure of live data, is this problem possible though ? ecu ignoring lambda with no eml\check engine lights? it seems to operate the same when it's disconnected and the dashboard lights work .