Fuel trims suddenly not stabilizing [Archive] - GrandAmGT.com Forum

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realestdriver
08-11-2011, 10:23 PM
I was on the way home last week on a 108 degree day and my car stumbled twice doing about 60mph. After that I looked up at my scanguage and saw that my fuel trims were heading south. So far I've checked the MaP sensor, MAF sensor, grounds, swapped fuel injectors and harness(Been on my to-do list) and other connections. I have hptuners, so I scanned the car and came up with mostly -10 to -14 on my ltft histograms, except for idle. Previously my fuel trims has been +4 to -4 ST and LT. I'm running out of things to check out now, what you guys think?

AleroB888
08-11-2011, 11:22 PM
I was on the way home last week on a 108 degree day and my car stumbled twice doing about 60mph. After that I looked up at my scanguage and saw that my fuel trims were heading south. So far I've checked the MaP sensor, MAF sensor, grounds, swapped fuel injectors and harness(Been on my to-do list) and other connections. I have hptuners, so I scanned the car and came up with mostly -10 to -14 on my ltft histograms, except for idle. Previously my fuel trims has been +4 to -4 ST and LT. I'm running out of things to check out now, what you guys think?

Less than usual vacuum reaching the FPR, defective FPR (inconsistent operation), exhaust leak near O2 sensor, heat soak of MAF sensor, much higher ambient temp since previous tune..............

However, most of those would effect LTFTs at idle as well.

realestdriver
08-11-2011, 11:32 PM
adding 2 check list. . .