Hi,
I have got problem with my car's emission control system and get a MIL light up with the error code:
P2096, Catalyst trim system too lean, bank 1
P2099, Catalyst trim system too rich, bank 2

I have found threads here that discuss how to solve it, but no one that I have found has any answer how they solved the problem at the end.

I interpret the error code like this. When engine idle the vacuum is high and that's causing the error code P2096 because of vaccum leakage. When run at higher speed and with load the vacuum goes down and now it gives too rich and give error code P2099. The system is disturbed by the vacuum leakage and working with wrong parameters because of the self learning regulation system.

When starting to solve this I replaced both upstrem O2 sensors, even if it was not necessary. I have also tested all fuel injectors and they are ok, I replaced the O-rings here too.

I found a leak at one of the valve covers and the oil stick O-ring looked bad. Fixed that.

It works much better now but not perfect and the MIL lights after 16 miles driving.

Next thing to investigate is if there is a leakage under the throttle body and a bad O-ring.

I try to document what I'm doing, both for myself and others that have simular problems.

It's here on my homepage:
http://astrofriend.eu/vehicles/my-ca...-problems.html

Anyone that have solved a problem like this or have ideas where to look?

/Lars

Homepage:
http://astrofriend.eu/