My short term fuel trim on bank one is 24.22
my bank 2 short term trim fluctuates with driving.
long term on both are 1.56

O2 sensor bank one, sensor one is not fluctuating and shows 1.020 on the UltraGauge if my memory serves. It doesn’t change with driving.O2 bank 2 sensor 1 does fluctuate with driving.

So working backwards from the O2 sensor, I’m thinking it’s a bad O2 sensor, a bad wiring harness, vacuum leak in one or more injectors on bank one or a leaking exhaust manifold on bank one.

Don’t think it’s intake manifold because it’s only on one bank. And anything else upstream of the intake manifold I think would affect both banks .

Anyone got any thoughts before I start throwing $$$ at this?
tia,
dcphotos

 

Symptoms are same as when I had a bad O2 sensor on my '96, also with no MIL or code for bad sensor.

To be thorough, someone may suggest swapping O2 sensors (both upstream) to see if the problem follows left to right.

 

JohnZo,
Thanks, that’s good to know.
We are on the road right now in Bryce Canyon. Spent last night in Farmington, NM. I stopped by Harbor Freight there and bought some tools to do the swap.
fingers crossed this works
dcphotos

 

all I see is the correct tools, for the job.

 

Good luck with your field repair. Maybe verify the O2 wrench is 17 mm. Our sensors are a little oddball, 18 mm is more common I think.

I have had my best luck with a 17 mm angled box end wrench, cut the wire first. Then use an open end wrench to install. The offset socket can damage the sensor up high if not kept very straight, and it's difficult to keep straight.

I have read posters claim disconnecting the O2s forces the ECM to use default values. One poster claimed improved fuel economy that way.

 

I am very suspicious of better fuel economy, but if a bad O2 sensor is really the culprit, disconnecting it might get you home, running great. But, if the ECU is sensing fuel out of range, hasn’t it already gone to open loop and running on the default settings?

 

So I swapped the b1s1 for b1s2
That was easy enough. Now, b1s1 is talking. S2 is now stuck at 1.020 like it was before I swapped it.
The sensor was damaged when I hit that boulder that cracked the oil cooler in the plastic radiator.
You can see in the pics it’s “crimped”.
Just happy to get this sorta sorted out. We left Zion NP yesterday and still have two weeks of vacation to go.

 

Thanks for letting us know the outcome