Search results
-
2
Possible Vacuum Leak, With Graphs
Fuel trims from cold start overnight with 30 Minute drive at near constant speed and incredibly flat.- 2001LSHoe
- Post #8
- Forum: Engine & Drivetrain
-
2
Possible Vacuum Leak, With Graphs
Below are graphs of the rear o2 sensors… is this an indication that the cats are going out?- 2001LSHoe
- Post #7
- Forum: Engine & Drivetrain
-
2
Possible Vacuum Leak, With Graphs
I did new plugs and wires, fuel filter and cleaned MAF all within the last year. I initially had this issue last winter on a morning when it got down to -15F. In the winter time the symptoms are much worse. The car had 90,000 miles and was a one owner when I purchased it in 2022. It now has...- 2001LSHoe
- Post #6
- Forum: Engine & Drivetrain
-
2
Possible Vacuum Leak, With Graphs
Yes, after it warms up all the fuel trims are +/- within 10% and very rarely outside of 5%. In fact, the only time I see the fuel trim at these levels is after an overnight start up. I've even tried running it in the morning working through lunch and trying in the evening after it's sat for 10...- 2001LSHoe
- Post #5
- Forum: Engine & Drivetrain
-
2
Possible Vacuum Leak, With Graphs
Thinking I have a vacuum leak. I get the really high STFT only on startup after leaving it sit overnight. It causes random misfires. It doesn’t always pull a code. If anything the check engine light flashes but it doesn’t register a misfire on a particular cylinder. Although cylinder three seems...- 2001LSHoe
- Thread
- Replies: 9
- Forum: Engine & Drivetrain
