Hi
Today I bought a new OBD II/ EOBD meter that has live data stream on it to try and correct a mis fire that has been plaguing me. I have a 2001 blazer 4.3 vin W. After doing the test I noticed that the long term fuel trim on bank# 1 was running really high ( 8.6 give or take) this number stayed pretty consistent in both the idle range ( 600 rpm) and cruising range (2000 rpm). the short term fuel trim on bank # 1 was around -1.6 @idle and +2.0 at cruise. Bank #2 stayed at around 0.0 to 0.8 on both short and long term at both ranges so im pretty happy with that. Im thinking that I may have a bad ( or dirty )O2 sensor on bank #1 side. I recently had a spider that went bad on the #5 cylinder and was dumping gas into the intake. I am wondering if that could have "fouled out " that sensor. I would be very happy to hear any other input that any of you may have. Thanks in advance.

 

It is possible that you have fuel fouled the sensor, but a LTFT1 of 8.6 isn't outside the realm of a properly functioning engine. How does the B1S1 O2 sensor output look? What is the cross count value? How active does it look while idling & cruising down the road?