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Joined: Mar 2002
Posts: 18
New CEG\'er
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OP
New CEG\'er
Joined: Mar 2002
Posts: 18 |
4cyl 95 Contour, automatic, 100k miles. When at full stop, the engine's RPMs jump noticeably every 5 seconds for about a second. Between the jumps the RPMs seem to be normal. When driving slowly (i.e. through a school zone) the car slightly jerks forward at the same rate as at idle. When driving at >20 mph the problem either does not exist or is not detectable. No CEL, no other side effects. Looks like the fuel economy is unaffected.
Any ideas?
Has anybody had this?
I searched the archives but nothing similar popped up...
Thanks!
95ContourGL
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Joined: Oct 2002
Posts: 2,408
Hard-core CEG'er
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Hard-core CEG'er
Joined: Oct 2002
Posts: 2,408 |
Does your A/C work properly?
"Those who cannot remember the past are condemned to repeat it" -George Santayana
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Joined: Sep 2002
Posts: 1,788
Hard-core CEG\'er
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Hard-core CEG\'er
Joined: Sep 2002
Posts: 1,788 |
Your IAC (Idle Air Control) valve is getting old and cranky. Time for a new one, probably.
Turn your climate control to OFF and see if the problem goes away. The IAC is supposed to compensate for the extra load that the A/C compressor places on the engine when the compressor clutch engages so some increase in idle speed is normal. Sounds like your IAC may be overshooting.
Before replacing anything, do check your A/C system for proper charge. It sounds like it is short-cycling and may be contributing you your symptoms.
The IAC has very little effect on intake air above 20 mph.
Steve
98 Contour SE Sport 2.5 Duratec ATX The wifey's car
89 Taurus SHO - 246K miles
94 SHO ATX - 190K
1997 F-150 5.4L ATX - The Workhorse 150K.
ANY THREAD WITH "OMG" or "WTF" ETC IN THE TITLE WILL BE IGNORED!
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Joined: Mar 2002
Posts: 18
New CEG\'er
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OP
New CEG\'er
Joined: Mar 2002
Posts: 18 |
Thanks guys for the clues...
My problem is independent on the A/C. The A/C may be off or on and the RPMs go up every 5 seconds. Sounds like it is the IAC then. Is it a dealer part only?
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Joined: Oct 2003
Posts: 5,143
Addicted CEG\'er
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Addicted CEG\'er
Joined: Oct 2003
Posts: 5,143 |
That, my friend. is the IAC, I need to replace mine, it does the exact same thing. I just dont have the money to do it. Im going to order a Ford Repair CD sometime soon....
If you are a "do it yourself" kind of person, then I suggest getting a Ford Service CD and some ramps and getting under the car to replace it.
98 Corolla LE 1.8L DOHC 1ZZFE
TEIN H.Tech Springs
Tokico HP series Struts
Short ram air intake
Tsudo Axel Back Exhaust
... if a jelly fish stung me.. would you pee on the wound?
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Joined: Mar 2002
Posts: 18
New CEG\'er
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OP
New CEG\'er
Joined: Mar 2002
Posts: 18 |
Is IAC a dealer part only or is there a good aftermarket source? Definitely I would like to replace it myself. BTW, I just finshed going through my Haynes manual but there is nothing about IAC. So dealer CD you say... how much is it? A few hundreds I would guestimate...
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Joined: Feb 2003
Posts: 1,012
Hard-core CEG\'er
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Hard-core CEG\'er
Joined: Feb 2003
Posts: 1,012 |
Na man its like $70 and a really simple install.
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Joined: Sep 2003
Posts: 1,246
Hard-core CEG\'er
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Hard-core CEG\'er
Joined: Sep 2003
Posts: 1,246 |
Get in touch with Bill Jenkins. He'll give you a discount. As far as replacing the IAC, all you need is to remove two bolts. Make sure you get the gasket for it too. You don't want any intake leaks.
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Joined: Mar 2003
Posts: 160
CEG\'er
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CEG\'er
Joined: Mar 2003
Posts: 160 |
I have the exact same car you do, only I have a bit more miles. I was experiencing the exact same problem for a long time. I suggest you do a search for "Idle surge problem fixed" under troubleshooting and try my solution before you spend any money on replacing items that you don't know if they are bad or not. Good luck
95 Gl Zetec Atx
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