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Tuner
Lean idle sitting for 5 minutes
G8 with E38. Has been tuned for many months, runs great, fuel trims +-2. Was doing some logging yesterday for something else and noticed something while idling. I was sitting for maybe 10 minutes. Fuel trims went lean, 5 to 10 to 15 to 20. Both banks are even. Does that indicate a vacuum leak, a leak between MAF and blade, or something else? Thanks.
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It could be several things causing this.
A datalog may help us diagnose it.
First of all, I have a few questions for you.
Does the lean condition go away when cruising?
Is fuel pressure within spec?
What was the IAT reading when this occurred?
Have you cleaned the MAF lately? Are you running an oiled filter?
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Tuner
Lean does go away when cruising. My fuel tables are good everywhere else. Just noticed it because I was sitting the other day. Have not checked fuel pressure. IAT's did go up. Ambient was 30 degrees. My IAT's were about 32 while driving. Got up to 50 by the time it was really lean. Have not cleaned MAF lately and no oil filter.
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best would be having a wideband and put the car in open loop to see whats going on, BAD o2 sensors could cause this
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Tuner
Ok. I'll try that. Thanks.
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