Please Help - Car idles at 25 MPH

[rmanick1]

Please Help - I have a 1999 Taurus with a Duratec engine. If I take my foot off the brake, the car starts to increase speed and even shifts into the next gear and will go about 25 MPH without touching the gas. I changed the Throttle positioning sensor and the Idle intake valve and even disconnected the cruise control but it still acts the same. I get no error codes from the engine. Any suggestions!!!

[All4Ford]

i have the same problem with my 97 vulcan taurus and i am yet to find a fix im trying some STP style fluid to see if its maybe the throttle sticking but im not sure as to what will fix the problem yet please keep me posted

[Froze_Tread]

First off if u got an automatic transmission the tourque converter is going to always be pulling u forward and u need to use the brake to stop this. If any car was let go long enough i think it would hit 25 thing is from what u describe it happens pretty quick so i am wondering what the rpm gauge is reading as the break is applied and after u let go. Does it climb. Its acting like the tourqe converter is locking up to much but that would also make the car whant to die when the brake is held at a stop. But if it was me id be looking at the rpms and wondering what the tranny is doing.

[rmanick1]

To: Froze_Tread - You have provided an interesting theory to the problem and you may be correct. To provide you with a few additional facts and to answer your questions: The tach reads about 900 RPM’s with the transmission in drive with the brake applied. When I release the brake, the car immediately starts to accelerate. It takes 30 – 40 seconds on average from a dead stop to reach 25 MPH. You can watch the tach as it slowly climbs to 1200 RPM’s after releasing the brake. The car would shift into second gear as it gains speed and start increasing again. When I put the transmission into neutral or park, it immediately revs up to about 1200 – 1300 RPM’s and then slows down within 5–10 seconds, I assume as the computer reads the engine speed and sends a signal to slow it down. It does this whether the car is cold or hot. In the last few weeks when this problem started, I did notice that when I came to a dead stop, the car would occasionally vibrate and stall as you mentioned in your comments, but would always start right up.

Now the questions - Is there any way to test your theory that the problem involves the torque converter? Would a transmission shop be able to determine what the problem is without taking it all apart? How difficult is it to replace the torque converter? Any other suggestions or comments?

Thanks for all your help!!!

[Car Pal]

your engine is getting air from some place other than the throttle body.check behind the intake near the throttle body for a loose or broken vacuum line

[Froze_Tread]

Easy way to check for a leak that i use is to use a can of carb cleaner it will immieditly change the engine rpm since its a source of fuel. Tourqe converts are not to hard to change by the seasoned mechanic and can be diagnosed usually without removing the engine. Id would try Car_Pal's idea since it is cheaper and i have had it happen before. Mine usually are leaking at the EGR valve. U might also be noticing a jult when putting the car into drive or reverse. Feeling like the car is slamming into gear.

[mr_tw]

we had the same problem with my dad's 1997 Duratec Taurus and to fix the problem all we had to do was change the air filter and spark plugs, my uncle (certified Ford Mechanic) said that somtimes when one of these parts fails or gets worn out the engine computer realizes that the engine isn't quite running right due to one of these problems and to get it to run a little better it will actually increase fuel delevery or do other things that can cause your car to idle higher the other thing it could possibly be would be the fuel filter, I've seen many problems dissapear when the fuel filter gets replaced, so thats another cheap repair that you may like to try

[cgregor2]

I had the same problem. I think it was the Throttle Position Sensor was bad. Replaced that and car ran perfect.

[beth1030]

my 93 taurus had the same problem too....there is a black box by the brake pedal and this box controlled the brake lights and i guess the power for speed....when it acted up...the car would downshift and would not go any faster than 25mph....i was pushing it if i hit the gas and made it go 35mph.....the engine made a loud noise when i tried to speed up....and when it would kick back in...after 2 minutes...it would upshift hard and would kinda kick the car......it finally went bad and caught on fire.....i replaced it and the car ran fine for about a week....then it downshifted again and stayed in the 25mph speed......and it made this loud clanking sound like flippers were flapping.....and i was told that it was the lifters that went bad.....i havent fixed it yet....the car has had it and im using it for parts.....but just out of curiosity....how many lifters are there in an engine and is it costly to get it repaired