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Discussion Starter #1
Hi, all. I have done some checking on my foci, and cannot figure out what the issue is. I have an idle fluctuation that goes from 600-1000 rpms. When using any electrical it causes it to stumble as well. I have replaced all motor mounts, with motorcraft. Cleaned the maf, cleaned the throttle body, and still has rolling idle issue. Any ideas, or know causes for this? Also no codes come up on scan tool. I am kind of stumped.
 

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charging issues ? low voltage can cause idle stumble. check all ground connections test alt output voltage check battery too ..

vacuum leak ? ( Brake booster vac leak, How does the brake peddle feel ? ) dirty injectors ? when is the last routine maint ? plugs oil & filters ?
 

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Discussion Starter #3
This car has always had a squishy pedal, and noticed when I start it cold it's rock hard sometimes. So I can say I feel there is a vacuum leak. As for the idle jumping around when I use power, not sure what to check. I have had battery and alternator checked. They are okay. Anything else? Tpi ? Or some other idle regulating sensor. I had heard of crankshaft position sensor possibly being a problem as well. From what I've read on these cars, a pile of them do this same rolling idle.
 

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Discussion Starter #5
One more thing I have done a test on the booster and it always checks out fine. When starting and using sometimesoon its rock hard to push, bad check valve or small leak? Trying to put everything I know out there.
 

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also I forgot about the IAC as a possibility

my brakes are the same almost like they need to be bled. spongy one time then harder the next. I read some where the booster could have an internal vac leak. it 'll bitch to change that. throttle position sensor could be an issue IMO try the cheapest repair first before spending cash

let us know
 

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Discussion Starter #8
Thanks again everyone! I did go through vacuum, had smoke test done. Found vacuum to be in normal range. Checked the booster, seems to be okay as well. As far as the charging system, battery, and alternator check out too. Which still has me stumped, because it has excessive drain when using electronics. I will be replacing the +, - cables just to be safe, they are pretty well corroded. So hopefully that may help. On to the tps. As far as idle control on these cars, is it the tps, and the ecm that controls this? When I do change this part, is there a proper relearning procedure?
 

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Discussion Starter #9
So this car has had a lot checked out. Cannot find any vacuum leaks. Booster checked out okay. Sprayed everywhere with spray to get a shutter. I have cleaned throttle body very well, looks like new. Problem still persists. I ordered tps and will be installing this week. Has anyone ever had a solid fix for the rolling idle. Mine goes from 600's to 800's rpm. Are the computers possibly bad on these cars ? At my wits end here with this car. I love this car, and have not lost hope yet.
 

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The electronic TB may be the issue itself, that's the only control on your version (No IAC like earlier models).

Throttle % would be the item to check even before replacing the TPS, or now before/after since a new one is on the way. You'd want to see it changing to try & adjust RPM as the speed changes.

Test both with and without variable loads, it's supposed to adjust for things like turning on electrical items loading the alternator/engine or turning on A/C.

If it's no longer able to do those small changes consistently that's the expensive issue.
 

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Discussion Starter #11
Thanks for some insight on this. It has been something I have been picking at for awhile. Being it's my daily driver and mostly used on highway I just deal with it. If I bust out the old multimeter what are some values I should be looking for on each wire?
 

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Discussion Starter #12
Where do I find relearning procedure for the car? I want to fully reset pcm. I am also looking at buying a sct tuner as well. Has anyone had success in dialing in a nice idle with that tuner? Thinking it might be last resort after tps.
 

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Old Phart
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For relearning, disconnect battery for a while then to speed up the process when you first fire it up let it idle until it drops to a normal low idle.

Forget the multimeter, you need to look at reported throttle position with a scan tool.

And an SCT flasher/scanner is NOT the way to do it. Can't adjust idle/idle quality that way on your own. And a tuner can't fix it either while there's still a possible mechanical issue.
 

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Discussion Starter #14
What kind of scan tool should I be using, I am trying to do this on a budget. Bringing it in to the dealership in town is a no go. They have had no success in resolving this issue. They say the surging is normal. Can I install a program and get a cable to get reading on this?
 

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Discussion Starter #15
I was also looking at getting sct tuner for future upgrades, was not sure if it could increase idle speed a little bit, or if it would take care of bouncing idle.
 

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Get the Chinese clone Ford IDS and VCM from eBay. It's Ford's own dealer scan tool. Just the hardware is a knock-off but it works fine.

Sent from my A0001 using Tapatalk
 
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