Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1997 Ford Probe Base, AutomaticFACTORY OEM SERVICE PROCEDURE
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.
- 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.
- 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.
- 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.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
Rather have a pro handle this?
A certified mobile mechanic comes to your home or office. They bring the tools, you stay comfortable. No tow truck, no waiting room, no surprises.
Comes to youSame-day available12-month warranty
Get a Free QuoteNo obligation. See pricing before you book.