Quote:
Originally Posted by waypoint
The ECM might have set one or more codes in Pending state...whip out your scanner and check for them.
From your description, it sounds like the idle problem only happens when the engine is up to temp and in closed loop mode. This is usually a malfunctioning mass airflow sensor or upstream oxygen sensor.
Scan the Long Term Fuel Trim values for both banks, both at cold idle and after fully warmed up. Post the data and we'll see what's happening...should range from +5% to -5% on both banks, with values within ~2% of each other.
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I finally got a scanner out and it had a P0301 Cylinder 1 Misfire Detected fault. I fixed the heater core hose leak which was dripping on the bank 2 A/F sensor. I was expecting the misfire to be on bank 2 because of this. I did some swapping of the spark plugs and ignition coils on cylinders 1 and 3 to see if the misfire would move with them. It did not, the misfire stayed on cylinder 1.
I drove it some more and managed to get a P0171 System Too Lean (A/F Lean, Bank 2) fault. I checked the Long Term Fuel Trims and bank 1 was +27.3% and bank 2 was +7.8%. I should note that I had the negative battery disconnected earlier in the day and I drove it maybe 8 miles before checking the LTFT.
I'm guessing this means the Bank 1 A/F sensor is bad. Is the bank 2 sensor also going bad since it's outside of you +5/-5% range? Or does that not apply since the numbers seem to have reset with the battery disconnected. If I had time I would have swapped the A/F sensors to see if the misfire moved to bank 2. I guess I could try that later this week when I have time.