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Alex, ASE Certified Technician
Category: Ford
Satisfied Customers: 1161
Experience:  ASE Certified Master Technician, L1 Advanced Level Specialist
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Ford Taurus: I have 1 98 Taurus with revving problems. It always

Customer Question

I have 1 98 Taurus with revving problems. It always happens after I've been driving for a while at or near highway speed. As I've come to a complete stop, the engine revs (the vroom-vroom type). My only solution is to tromp HARD on the brakes, jam it into park and shut of the engine. Sometimes shutting of the engine fixes the problem, sometimes it takes a couple of tries over a couple of minutes. I've disconnected the cruise control cable but that didn't help. This started happening years ago, but only once every 2 or 3 years. Now it's happened 3 times in the last couple of weeks.
Submitted: 1 year ago.
Category: Ford
Expert:  Alex replied 1 year ago.
Hello, My name is***** for using Just Answer.
Let me ask, when the engine RPM is high when it should be at idle, how high are the RPM's on the tachometer?
Customer: replied 1 year ago.
I've never let it rev completely, nor have I actually checked the tach when it does rev, but I'd say it essentially immediately goes to about 3000 rpm. It's rather a fright when you're stopping in traffic with a car (or in one case a pedestrian) right in front of you. When you jam it from OD to park, it even makes the tires screech (scaring the pedestrian as well as those of us in the car). It happens immediately before or right when the car comes to a complete stop.
Expert:  Alex replied 1 year ago.
Thanks for that information. The first thing to do is remove the air intake tube from the throttle body inlet. This is the tube that goes from the air filter box to the throttle body.
With the tube off you will be able to look into the throttle bore and see the throttle plate. Rotate the throttle lever by hand and watch the throttle plate open and close. Make sure it opens and closes smoothly all the way and does not bind in any spot.
Check for dirt/gunk build-up in the throttle body around the throttle plate. If it is dirty, clean it using lots of throttle body cleaner and a clean lint free cloth. Spray the cleaner into the throttle body while holding the throttle lever open with the other hand. Clean and wipe as much gunk out of the throttle body as you can on all sides, particularly around the throttle plate where the plate seals against the throttle bore.
Gunk build up here can cause the throttle plate not to close completely and cause an over-rev condition.
Please let me know what you find.
Customer: replied 1 year ago.
I can give it a try. It's hard to know if whatever I try really fixes the problem as it may not happen again for months or even years. However, I'm having trouble relating the fix to the symptom. Generally, I have had my foot off the throttle for several seconds and have had my foot on the break. In one case I was letting people out in front of work. I had driven down a toll road for about 10 mile as 60mph and then about 2 miles at 45mph and then a few hundred yards at 25mph then braking coming up to the building with a sharp 90 degree left turn coming to a complete stop. In that turn, the nose of the car travelled little more than the length of the car and I had had my foot on the brake for 50 feet or so traveling at probably 5mph. For the last couple of minutes, the car hadn't been going much over an idle speed. Then right as the car comes to the final stop (essentially tires had stopped, but the car was still doing a little lurch at the end of motion), the engine suddenly revved. It's almost as though the cruise control had gotten suddenly confused, however I had already detached the mechanical linkage between it and the throttle body.
Expert:  Alex replied 1 year ago.
It could be a bad Idle Air Control valve. But I would check for a dirty throttle body first. If it is very dirty that is most likely the problem. If it is not that dirty it is much more likely to be a faulty Idle Air Control valve.
Another thing to check is the primary throttle cable. Disconnect it from the throttle lever and make sure it slides smoothly inside the sheath by hand. If it is binding or sticking, replace it.