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 3.4L article in the ENGINES section for removal and installation procedures.
- Rotate crankshaft in direction of normal operation until camshaft lobe is opposite lifter shim. (Scheme 3) Using feeler gauge, check clearance between camshaft and lifter shim. Replace shim if clearance is not within specification. See COLLAPSED VALVE LIFTER CLEARANCE table.
- To replace shim, insert Lifter Compressor (T89P-6500-A) under camshaft, next to lobe, and rotate downward to depress lifter. Insert Lifter Holder (T86P-6500-AH), and remove lifter compressor. Using compressed air, lift shim and remove it using a magnet.
- Determine shim size by number on bottom side of shim or by measuring shim using a micrometer. Install appropriate shim with number facing downward. Repeat procedure for each valve.
| Application | In. (mm) |
|---|---|
| Intake | .006-.010 (0.15-0.25) |
| Exhaust | .010-.014 (0.25-0.35) |
COLLAPSED VALVE LIFTER CLEARANCE
Scheme 3
IGNITION TIMING
Note. Ignition timing is not adjustable on 3.4L models.
| Application | Degrees BTDC @ Idle |
|---|---|
| 3.4L SHO | (1) |
| (1) Information not available. | |
| (1) | Information not available. |
BASE IGNITION TIMING
THROTTLE POSITION (TP) SENSOR
TP sensor is not adjustable. Ensure TP sensor is properly installed. See THROTTLE POSITION (TP) SENSOR under FUEL SYSTEM in REMOVE/INSTALL/OVERHAUL article. If additional test procedures are required, see TESTS W/CODES article.