Idle Speed & Mixture
NOTE:
Idle mixture on fuel injected models is controlled by the Electronic Control Module (ECM) and is not adjustable. Controlled idle speed and IAC count can be checked using scan tester. See CONTROLLED IDLE SPEED & IAC COUNT table.
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 |