If you have a Check Engine Light:
- Post the code. If you don’t know the code, we can only guess.
- Post the code description. P0123 is not helpful. “Throttle position sensor circuit high input” is helpful.
- Tell us how long the CEL has been lit.
- Tell us what you were doing when the CEL came on.
- Tell us what changes (if any) you have recently made to the car.
If you have a data log:
- Make sure it has a useful set of parameters. If you don’t know which parameters will be useful, see section 6 of how to make a useful data log.
- Please trim the unnecessary stuff. If you’re asking about a pull, don’t post a log with 20 minutes of cruising and a pull somewhere in the middle.
- Start your pulls from 2000–2500 RPM, and end them near the redline.
- If your map can be posted (see rules here) please include it.
- Tell us what model and year your car is.
- Tell us what changes you have made to the car (intake, exhaust, fueling, etc).
- Tell us what fuel you’re using, and how hot or cold the air temperature was.
- Tell us what you see in the log. If you don’t know how to read the, read this first then guess. It’s OK to be wrong, but show us that you’re trying. If you are interested in learning, this is how you start. If you are not interested in learning, considering paying for help.