RPM stays high after stopping but drop to normal after a while.

Tiny
ALEXV55
  • 2000 FORD FOCUS
  • 2.0L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 165,000 MILES

I am trying to diagnose problem with high rpm which only happens after I drive above 45 rpm.

Background is that its ford focus with zetec engine. The car had low idle problem, it would stall after to coming to stop. I started checking for vacuum leaks and found collapsed pcv hose. Also checked pcv valve and found it was sticking and then IAC check revealed zero resistance at motor terminal so that was replaced too. Idle is now fixed.

After the repair on test drive, it has high rpm problem. Car starts and runs fine until I take it above 45 mph. When I let my foot off the gas pedal, the car keeps going. When I stopping the rpm stays around 1700, and then suddenly drop to its normal idle shifts down.

- I have checked throttle cable and it isn't sticking.

- I don't notice any vacuum leak, sprayed propane and starter fluid, no change in rpm.

- Scanner reading shows throttle position 18% at idle and changes with throttle movement. While driving when I let foot off gas, it drops immediately to 18% indicating closed throttle.

- maf is another story. At normal idle its at.2 lb/min. Goes up and down as I give it gas and let my foot off. But maf reading stays constant at 1.7 - 1.8 lb/min after I let go of the pedal after speeding over 45 - mph. It stays at this number even when I come to stop, rpm shows around 1700 and idle eventually comes to its normal reading suddenly as described above.

- stft and ltft both are positve at idle. While driving ltft remains high, around +8, while sf fluctuates between as +1.6, 0, and - 2. Xx,


- o2 sensor reading looks normal

Do you have any guidance how to go about diagnosing the problem.

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Saturday, August 27th, 2016 AT 3:31 PM

7 Replies

Tiny
2CARPROS RENEE
  • ADMIN
  • 679 POSTS

Yep, this engine had this problem. Once you fixed these problems the computer must relearn the engine which can take a while. The factory has a computer that can clear the adaptation which will fix the problem if you don't want to wait it out. Try clearing the codes anyway to see if that helps.

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Wednesday, August 31st, 2016 AT 6:36 PM
Tiny
ALEXV55
  • MEMBER

The problem was the new IAC I had replaced. Apparently this car is picky about the IAC valve and insists on OEM. Off the market from parts store don't work as mentioned in many threads on the net. I replaced it with the original motorocraft and everything was fixed.

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Sunday, July 23rd, 2017 AT 5:20 PM
Tiny
2CARPROS KEN
  • ADMIN
  • 9,458 POSTS

Nice work, we are here to help, please use 2CarPros anytime.

Cheers, Ken

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Monday, July 24th, 2017 AT 3:29 PM
Tiny
HIALIEN13
  • 2000 FORD FOCUS
  • 2.0L
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 120,000 MILES

Rpm to high(1500) when the car is in drive and ac on, when ac off runs perfect. I have tried 2 new iacv, 2 tps, maf sensor, new pcv valve, cylinder head done at machine shop. No vacuum leaks. Tested with a snap on scanner and every thing looks fine. Don't know where else to look or test.

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Monday, July 24th, 2017 AT 3:30 PM (Merged)
Tiny
HMAC300
  • EXPERT
  • 49,839 POSTS

Try cleaning the throttle plateon both sides with choke cleaner.

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Monday, July 24th, 2017 AT 3:30 PM (Merged)
Tiny
DAVEMAX69
  • 2000 FORD FOCUS

Electrical problem
2000 Ford Focus 4 cyl Front Wheel Drive Manual

my car has had this problem for about a year heres what I know heat is a factor the car has to be warmed up about an hours drive time before it acts up outside temp also plays into to it if it is hotter outsidde then it sppeds up the problem, all winter no problem. The car starts to rev when you are tring to stop you can have it out of gear clutch in or out it still will do it, you can knock it dowm sometime by shifting to a higher gear it will rev between 2000 and 4000 rpm but has got as highas5000 once. We have replaced the computer no luck their, clutch seems to be fine my macanic is stupmed I have no dependable car can you offer any suggestions?

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Monday, July 24th, 2017 AT 3:30 PM (Merged)
Tiny
LEGITIMATE007
  • EXPERT
  • 5,215 POSTS

Well, first I would check the throtte position sensor and after that the idle air control valve. Then mapp sensor if none of those, solve the problem

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Monday, July 24th, 2017 AT 3:30 PM (Merged)

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