Idle Speed & Mixture: Gasoline: Notes
NOTE:
DO NOT
attempt to adjust idle mixture and idle speed, which are controlled by the Electronic Control Module (ECM). Incorrect idle speeds are normally caused by dirty throttle plate or vacuum leaks. Ensure all vacuum components are functioning properly.
CONTROLLED IDLE SPEED & IAC COUNT
| Application |
Idle RPM |
IAC Counts |
| 2.5L TBI |
| "S" Series |
| Auto. Trans. |
800 |
15-40 |
| Man. Trans. |
900 |
5-20 |
| 2.8L TBI |
| "S" Series |
| Auto. Trans. |
800 |
5-20 |
| 3.1L TBI |
| "U" Series |
| Auto. Trans. |
600-700 |
5-15 |
| 3.8L PFI |
| "U" Series |
| Auto. Trans. |
650-750 |
16-20 |
| 4.3L CPI |
| "L" Series |
| Auto. Trans. |
625 |
5-50 |
| "M", "S" & "T" Series |
| Auto. Trans. |
550 |
5-40 |
| 4.3L PFI Turbo |
| "S" & "T" Series |
| Auto. Trans. |
|
1-50 |
| 4.3L TBI |
| "C" & "K" Series |
| Auto. Trans. |
537 |
5-30 |
| Auto. Trans. |
650 |
20-35 |
| Man. Trans. |
550 |
2-20 |
| "G" Series |
| Auto. Trans. |
538 |
5-30 |
| Man. Trans. |
650 |
5-30 |
| "L" Series |
| Auto. Trans. |
625 |
5-50 |
| Man. Trans. |
600 |
3-30 |
| "M" Series |
| Auto. Trans. |
538 |
5-30 |
| "P" Series |
| Auto. Trans. |
650 |
20-35 |
| 5.0L TBI |
| "C" & "K" Series |
| Auto. Trans. |
500 |
5-30 |
| Man. Trans. |
600 |
5-30 |
| 5.7L TBI |
| "C", "G", "K" & "P" Series |
| Under 8500 GVW |
| Auto. Trans. |
525 |
5-30 |
| Man. Trans. |
600 |
5-30 |
| Over 8500 GVW |
| Auto. Trans. |
550 |
5-30 |
| Man. Trans. |
600 |
5-30 |
| 7.4L TBI |
| "C", "G", "K" & "P" Series |
| Auto. Trans. |
750 |
5-30 |
| Man. Trans. |
800 |
5-30 |