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Set Speed Fluctuates

WARNING: This page is about a different car, the 1997 Lincoln Mark VIII. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check for Servo Cable & Throttle Linkage For Binding  - Verify condition. Ensure engine is properly tuned. If condition occurs when cruise control is off, repair engine as required. If condition only occurs when cruise control is activated, check servo cable, throttle linkage, or throttle plate for binding or sticking. Repair as necessary.
  2. Check Vehicle Speed Sensor  - Unplug VSS connector. Measure resistance between VSS terminals. If resistance is not 200-300 ohms, replace VSS. If resistance is 200-300 ohms, check VSS circuit for open or short. If wiring is okay, go to next step.
  3. Replace Servo  - Substitute a known-good servo. Test drive vehicle and check for proper cruise control operation. If speed still fluctuates, check PCM for stored codes. See appropriate TESTS W/CODES article in ENGINE PERFORMANCE section.
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