Mondeo revs do not fall fast enough when coming off accelerator

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- Rockingrabbit
  
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posted
13 years ago

Mon, Aug 30, 2010 3:54 PM

1999 1.8 zetec Mk2 Mondeo. Had this problem since I bought it a year ago. Revs drop slowly when I come of accelerator or changing gear.

If I'm in 3rd gear about 1300-1500 rpm and come off accelerator. Revs hardly drop for 3-5 seconds and either forced to wait until they very slowly fall or have to change down or brake to reduce speed. Very tiring to drive around town.

It did improve it very slightly by cleaning air intake butterfly. Had some black goo around butterfly edges. Cleaning with carb cleaner helped and gives me some feeling of engine braking for some of the time, but revs still dropping very slowly when I come off accelerator. Drives a bit like a 1970's Ford auto gearbox. Appears to coast when I come off accelerator.

Shows no error codes on handheld tester. Not been on Ford workshop computer.

Rockingrabbit

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- Mrcheerful
  
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posted
13 years ago

Mon, Aug 30, 2010 6:05 PM

if it is the same as a focus (almost certainly) then you must not use carb cleaner on the butterfly, there is a label warning you against it on the throttle body. checking the output of the throttle position sensor should help with diagnosis, anything over a volt (should be 0.7) and the revs will stay high longer (between pins 2 and 3 , the lower two in the plug with it conected)

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- Rockingrabbit
  
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posted
13 years ago

Tue, Aug 31, 2010 11:00 AM

Ok, I'll try that and thanks for position of pins as will make it much easier. Didn't see any warning label. Local garage suggested there was probably black goo around butterfly and this might help and it certainly has. He just said not to squirt back up towards air filter as there is something delicate (sensor ?) that does not take kindly to carb cleaner. He warned me there would be a bit of white smoke and rough running for a few seconds when started. I let carb clearner evaporate as wasn't happy about that going through my fairly new cat, but worth it for the improvment.

Rabbit