ENGINE MECHANICAL
Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.
VALVE CLEARANCE
Note. Valve cover(s) must be removed before performing valve adjustment. See ENGINES article in the ENGINES section for removal and installation procedures.
IGNITION TIMING
Note. Depending on model, Pickup models use EEC-IV or EEC-Vsystem. EEC-IV PCM has 60-pin connector. EEC-V PCM has 104-pin connector. See ENGINE/VIN ID article for correct application.
Ignition timing on models equipped with EEC-V is not adjustable. Use timing light to check base timing. See BASE IGNITION TIMING table.
| Application | Degrees BTDC |
|---|---|
| 4.6L | (1) 8-10 |
| (1) With SPOUT in-line connector unplugged. | |
| (1) | With SPOUT in-line connector unplugged. |
BASE IGNITION TIMING
IDLE SPEED & MIXTURE
Note. Idle mixture is not adjustable. If idle mixture is incorrect, see TESTS W/CODES article.
Cold (Fast) Idle
Fast idle speed is controlled by the PCM. Adjustment is not required.
THROTTLE POSITION (TP) SENSOR
Note. Throttle Position (TP) sensor on gasoline engines is not adjustable. If TP sensor service is required, see CIRCUIT TEST DH in TESTS W/CODES article.