96 GC hesitation, rough running...

Jun 23, 2005 6 Replies
96, 2wd, auto, I-6

had a 171 code (lean), followed by 172 (rich) this means O2 sensors, eh? do I get new bosch ones, now I get a 138 code, meaning "O2 Sensor Circuit High Voltage (Bank 1 Sensor 2) Oxygen sensor input voltage maintained above normal operating range. so, the cat. sensorvolt. is too high.


the trouble with the vehicle is that it runs rough, and has severe hesitation. the intke is clean, has new TPS sensor.



here's the rub... this only happens when ambient temp is above 85F. early mornings, late nights, below 85, runs just fine... what am i missing, and what about the 138 code?



thanks


Oh, say it ain't so, Bill... please?

whas the cause of the 138 code? brand new bosch...

P0138-1/2 O2 SENSOR SHORTED TO VOLTAGE

When Monitored: With battery voltage greater than 10.4 volts, engine running for more

than 4 minutes and coolant temperature above 180°F.

Set Condition: The oxygen sensor voltage is above 1.5 volts

Once again Bill, You have been confirmed as Master of all he surveys. It was indeed the fuel pump. Thanks.

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