BlackBear

The code stands for Bank 2 Post Cat Fuel Trim Too Lean.

I have changed both O2 sensors on bank 2 with no success.

At 2000 RPM the funky reading are gone and everything looks good again. Check engine light always gets triggered at idle.

The bank 1 post cat O2 sensor has very low voltage at idle. The voltage goes up to about equal with bank 2 at 2000 RPM. It feels like the DME is making a change or a valve is opening or closing to change the value. At the higher reading after 2000 RPM I never get a CEL. Could BANK 1 be the cause for code P2198 because a wrong reading from the maybe faulty bank 1 post cat O2 sensor is causing the DME to make the wrong adjustments? I don't think that bank 1 has an internal engine problem because sensor 1 on bank 1 should have alerted to that and it doesn't.

Disregard P1090, I had unplugged the MAF sensor to observe how it changes the numbers.

Below are the PIWIS reading. Is there anyone here who can determine what the problem is?

Cemlo

I'm not reading too much into that data but like you said nothing is reporting for the bank 1 side code wise so I wouldn't add to the equation at this point (apart from a ref a to the Volts for bank 2?). Between bank 2 sensors and the MAF trim lvls are calculated, so we have to assume the error codes/erroneous values are the real indicators whats wrong. I know you have changed both sensors but I would be checking connections and testing the sensors (resistance check) to confirm as best as you can they are working correctly.

I can say this from past experience, a new O2 sensor wire pulled out on installation for me so a loose wire/bad connection could be happening. Another concideration is allowing for a cold engine effecting results, MAF/heaters on the sensors - are you getting the exact same issue on a warm enging start or just cold?

harveyf

This may help. I agree with @chemlo. The ECU can certainly make adjustments on both banks independantly of each other.

BlackBear

Thank you both for your help.

I have checked and cleaned the connections on bank 2 when I replaced the O2 sensors.

I just searched the surface of the cat pipe for leaks. There was no sound to indicate a leak. When I used the stethoscope I could hear a tiny leak to the rear of the pre cat sensor. I plugged that hole with JB weld for exhausts. It says it is good for up to 1000 degrees F. We will see.