How do you fix idle surge on a cammed LS?
A surge is the idle control fighting itself. HP Academy's fixes, in order:
- Fueling first: make sure the air-fuel ratio at idle is right. Also check fuel trims bank to bank: PCM of NC notes that a big split between banks usually points to a vacuum leak, so smoke-test before tuning.
- Realistic idle target for the cam (about 800–850 rpm for an aggressive one).
- Enough throttle authority: raise idle "percentage max" from about 2% to 4% or more.
- Correct base running airflow from logged data, plus 1–2 g/s.
- Halve the adaptive spark (over/underspeed) tables so timing corrections don't overshoot.
See cam tuning.
Want to do it yourself? See who tunes it, and how to learn.
Confidence: medium — sources disagree or are limited; check the sources below.
Related questions
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Sources
- Remote (Email) Tuning with HP Tuners FAQ — PCM of NC
- LS Idle Tuning Basics With HP Tuners — High Performance Academy