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Weird Idle Again.....

6K views 23 replies 9 participants last post by  lildisco 
#1 ·
I've been trying to figure this thing out for awhile now. Some of you may remember my other threads on this, but it's been lingering for awhile now, I can't get my car to Idle Right. First off i don't have a tach so the RPM's are quesstimated. Second i have a Zetec with a Manual Transmission.

I start up the car and Idle's fine without touching the gas. The car is completly up to operating temp.. I jump in the car and drive it down the driveway. I shift from 1st to 2nd and the Idle hangs, not bad, but enough to make the shift into 2nd jolt the car. Come to the stop at the end of the Driveway push in the clutch and stop and the ilde is at a quesstimated 2,000 RPM's. Not nearly as bad as my previous situation. And it eventually comes down, after about 10 - 15 seconds to where it should.

That isn't bad, but if i were to pull up next to somebody, say a cop, they would think i'm getting ready to race them, just by the sound of my engine and exhaust.

Second Problem:

I'm driving down a 25MPH road in 4th and my foot is completly off the gas, but I'm staying at 26MPH unless the road goes uphill or downhill and the speed changes accordingly. Once i level out it goes back to 26MPH. Push in the Cluth and the Idle goes up again to a high RPM (quesstimated under 3,000RPM's) and doesn't come down untill i'm stopped for atleast 10-15 seconds.

What I've Tried and Replaced:

I tried to change the TPS and there was no change, but this was BEFORE i change the IACV. But when i changed the Throttle Position Sensor, Nothing changed, but I also got a Code. It was a Throttle Posistion sensor Low Voltage code. Changed back to the original TPS and code went away. While i had 2 TPS's i took it to my buddies shop who has a scanner and he said the computer thinks that it was under 15% load with both TPS's. I took the new TPS back to the place where i got it for a refund. After that, I unplugged the IACV and the Car Idled like Normal, thus i thought i might have found my problem.

I just replace the Idle Air Control Valve and that had the most drastic change. Idle is not nearly as bad. But it still hangs with the same results before i changed the IACV but not nearly as bad. I've checked countless times looking for Vaccum Leaks and to no Avail. I've sprayed Throttle Body Cleaner all over the intake Manifold and all the Vaccum Lines and my idle did not change. I even went to an extreme and took a propane torch not lit (ofcourse) with the car idling and the idle did not change again [:(] But if i Unplugg the IACV, my car Idle's fine. I rev the engine, while not moving, and it comes right back down. Drive down the road with the same result idle comming right back down and not hanging and my speed comes down accordingly. The only problem i've found, is that my Check Engine light Comes on with the IACV Unplugged.

I'm at Wits End here. I don't know what else it could be. My Car is technically under warranty, but i'm not willing yet to have them look at it and have them say something stupid like my exhaust is causing the car not to idle right. I will if i have to, but at a last resort. I will probally try to change the TPS again, but i was wondering if anyone else had any input. I'm also thinking that i might have a double whammy. Meaning my IACV and TPS can be bad but the IACV was more dominate cause than the TPS. Or I could have gotten both 'bad' parts right out the box. Not Likely, but ya never know. Any Input would be appreciated.

Thanks! [thumb]

P.S.

If anyone is comming to the Meet on Sunday (Spring Into Focus), then by all means, see if you can fix it. it's becomming highly annoying, I'm half tempted just to leave the damn IACV unplugged and deal with a CEL.
 
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#2 ·
In a bind, you could use the built-in digital tachometer on your dashboard display. I don't remember where I copied this from, but I'll paste the instructions at the bottom of this message.

As for your actual problem, is there any possibility that the throttle is mechanically hanging up? Bent shaft keeping the throttle from closing fully? Cable hangup? You said it idles fine when you start the car WITHOUT touching the gas, but starts acting up at the first shift (after you HAVE touched the gas) and continues afterwards. Maybe throttle really is hanging up. Just a thought..



1) Insert Key (do not turn it)
2) Press and hold the Trip-Meter Reset Button
3) While holding the reset button, start your car and continue holding the button.
4) Within 10 seconds, the display should change to "test" (written in a silly LCD font) and the needles will go nuts. No biggie. Release the Button.
5) Pressing the button will now cycle through some 15 different modes.

Breakdown of some of the functions:
1 Press - Shows a Gauge Sweep
2 Presses - shows all 8's on the LCD (LCD TEST)
3 Presses - illuminates all the bulbs on the dash
4 Presses - displays hexadecimal value for ROM level
5 Presses - Displays the hexadecimal value for EE level
6 Presses - Shows DTC Troubleshooting Codes
7 Presses - DIGITAL SPEEDOMETER - MPH
8 Presses - DIGITAL SPEEDOMETER - KPH
10 Presses - DIGITAL TACHOMETER
 
#3 ·
No the butterfly on the Throttle Body Closes right back after you left off the gas, that's why i'm thinking that it's something electronic. I have no after market Throttle Body either. My mods include:

SVT Snorkle, Volant CAI, FS UDP, Bosal Flex Pipe and Magnaflow Cat-Back.


I new about the tach mod and i also have a spare gauge cluster with a tach sittin in my trunk [thumb] my idle isn't as jacked as it was before, the IACV helped a lot.
 
#4 ·
Had same problem with an F150 here at the shop, if its revving it is getting air from somewhere else. Had high idle turned out pcv valave was stuck full open and pulling all the air from the vent tube getting its extra air it neede to run up that high without opening the throttle plate. When is the last time you changed it? This one looked fine, rattled like normal, spring was just weak from age. That is why they should be changed every 15k.
 
#5 ·
changed that out about 2,000 miles ago and didn't find any leaks or oil anywhere and the old one still rattled.
 
#6 ·
let me know if you figure out the problem. My focus does the same thiing and i have replaced

MAF
DPFE Senor
TPS
IACV
Vacum lines to the egr

next month it is going into the shop if i can figure it out.
 
#7 ·
Mine was an air leak ( very slight ) between my TB and the mani. I used some high temp gasket snot and it fixed the problem. Mine tested fine with carb cleaner as well... Worth a try if you haven't yet. Just a thin coat on both sides of the gasket.
 
#8 ·
mendevil said:
let me know if you figure out the problem. My focus does the same thiing and i have replaced

MAF
DPFE Senor
TPS
IACV
Vacum lines to the egr

next month it is going into the shop if i can figure it out.
There's more Vaccum Lines that need to be replaced. I'm told all the Vaccum lines run to the back of the Intake Manifold.

I guess putting some silicone around the Trottle body wouldn't be a bad thing, but i've sprayed Throttle Body cleaner and had a unlit propane torch all around it and my idle didn't change. But when i unplugged the IACV the car idles like it should [8]
 
#9 · (Edited)
If you had a vacuum leak that large which is unmetered air, your MIL would be on throwing lean codes trust me, small leaks do it. So if this truly was a vac leak problem your MIL would be on dont waste your time with vac leak checking, like you have found so far there is no change when sprayed with carb clean or propane. Although only way to be sure is watch your pid data for the short term fuel trims, and see if the 02's are reading lean, and short fuel trims are adjusting accordingly. Also for the record propane is the most effective way to check for vac leaks it flows around the item being test istead of hitting it in spots with pressurized carb cleaner which may actually force itself in and give inaccurate results as told by one of the Ford engineers. Also the aftermarket air filter element, and exhaust will definitely have a effect on the maf's ability to read accurately, seen it before. So dont think the dealer is telling you something stupid, and they are just blowing you off. They are telling you the same information that Fords engineers are telling us technicians, and i think the engineers know a little bit about the pcm's fuel strategy. It affects many model cars with the same mods not just the focus, look at all the problems the Ford superduty trucks are having with the pcm update, that now soley relies on the maf, they runn like total crap becuase of the aftermarket air and exhaust.
 
#10 ·
Alrighty, 2 IACV's and 1 TPS and i'm still having the same problem. This is getting real frustrating. Even changing the TPS, i still have the 4th gear going 26 MPH thing. I don't know what it could be!?! But when i did change over all the stuff, i did notice that it helped a lot and the problem is still there and is noticable, just not AS noticable. Car starts up Idle's fine 1st to 2nd shift is ok Revs hang, but not nearly as bad as before. Come to a stop push in the clutch and the RPM's shoot up to around 1,500 RPM's (questimated) and after about 10-15 seconds it idles where it should be. Again, if i unplugg the IACV it idles where it should. I don't think it's my DPFE Sensor because it's disabled from when the chip was installed and i couldn't find ANY vaccum lines.........any other ideas?[???:)]

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#11 ·
Morning Bump
 
#13 ·
Had a chip, did it with the chip, does it w/o the chip. Stock TB and TPS.........
 
#14 ·
I found 2 things out tonight. I swapped my gauge cluster out to 1 with a tach and noticed that the car eventually idles at 1,100 to 1,300 RPMs. I checked this with the analog tach and the Digital Tach on the cluster. With and Without the IACV Unplugged, the Car Idled at 1,100 to 1,300 RPMs. I noticed that the car would Idle right IF i had the IACV unplugged and the A/C on, it'd idle around 800 RPMs. As soon as i turned off the A/C the car would shoot right back up to the 1,100 to 1,300 RPMs.

Anyone have any suggestions?

Clicky Clicky
Clicky Clicky

You'll need quicktime

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#15 ·
I had the exact same problem for a week or so. Diagnosed - it was out of time and needed a new timing belt and stuff. Check your timing belt, it's likely the problem.
Either that or maybe a fraying throttle cable. If the throttle cable frays, it doesnt have the tension to completely close the TB, and therefore air is getting in constantly. You said when its been sitting and you start it its fine. Maybe that's because it's had enough time to gradually become tense and fully close the TB. Warm temps cause expansion, cool temps constriction...
 
#16 ·
I just recently found out that it's not idling around the 750 mark like it should. It's now idling around 1,100 mark when it decides to get there.
 
#18 ·
lol......damn it someone hopefully someone can give me some insight on what to do here.....
 
#19 ·
lildisco...when i watched your videos and your gauges i saw how your car ran nicely, and mine doesn't. it loses all power when it hits about 4,000 RPMs, it feels like its giving all its got to do pretty much nothing. Any ideas? I'm going to my mechanic on Tuesday I'll see if he has any insight on what could cause your idle problems. I noticed your CEL is on...what code is showing??
 
#20 ·
my CEL was from the IACV i unplugged it before the video was shot and it came on [thumb]

with your problem, have you tried to replace your fuel filter? Could be the problem. Also what year is your car? 2000 or 2001? those were the problematic years, you might wanna look at a fuel pump recall on that....
 
#21 ·
mines a 2000. went to the ford dealer in town and they gave me shit. charged me 65 bucks for diagnostics and didnt even replace the recalled fuel pump. said the problem was a fuel injector. I wasted my money on new injectors and it didnt do shit. im gonna go to a different ford dealer next week cuz it definitely seems like a fuel issue... fuel filter changed last week, new injectors, new plugs and wires, and thats all within the past week. now im of course piss broke... : ) will chat with my mechanic and hopefull give you some ideas...they're really cool where i go!! : )
 
#23 ·
^^ bump as well

this happens SOMETIMES on my 2000 sedan, 5 speed

sometimes when i notice im really flooring the gas and stuff, and im approaching a light to stop, ill down shift, and while im in 2d or 3rd, it idles very high, around 3-4k, and just stay there, it wont go down at all, it pisses me the he11 off, it just started happening about a month ago
 
#24 ·
I wish i could tell you what fixed mine. I changed the TB Gasket and it helped a lot. Then i changed my stock header/cat to the SVT Header and R/T hi-flow and it idles just fine. Actually sometimes it nearly wants to stall [dunno] I'll take that instead of idling around 3-4K
 
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