B: Set Speed Fluctuates

B1 Verify Condition Occurs Only While Using Speed Control
- Verify that engine is properly tuned.
- Verify that condition does not occur when driving without speed control.
- Does condition occur without speed control?

Yes
SERVICE engine as required. REFER to Powertrain Management/Computers and Control Systems.
No
GO to B2

B2 Check For Binding In Speed Control Actuator Cable And Throttle Body Linkage
- Check for binding or sticking of speed control actuator cable or throttle linkage and throttle plate.
- Make sure throttle cable bracket and speed control servo bracket are not loose.
- Are components OK?

Yes
GO to B3
No
SERVICE as required.

B3 Check VSS
- Remove VSS connector.
- Measure resistance across sensor terminals.
- Is resistance between 200 and 300 ohms?

Yes
CHECK continuity across Circuit 150 (DG/W) and 563 (O/Y). GO to B4
No
REPLACE vehicle speed sensor.

B4 Check Speed Control Servo Assembly
- Substitute known good speed control servo.
- Test vehicle for proper operation.
- Does system operate properly?

Yes
REPLACE speed control servo.
No
CHECK MAP sensor and EGR valve position (EVP). REFER to Powertrain Management/Computers and Control Systems.