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Discussion Starter #1
I just bought a turbo coupe for $300. It's a real hunk of crap. Outside of the body though, there are only some minor engine gremlins, one of which I'm narrowing down tonight. The engine has a hanging idle. After driving and warming up, the RPMs will hang up right around 2K, 2.5K, and 2.7K. Each time I drive the car, the RPMs seem to hang up just a little bit higher.

Now, I've already pulled the IAC and cleaned it. It did help to stabilize the car on start up and will hold an idle at any RPM strongly...eg, it doesn't seem like its pecking for an idle.

I've checked for a sticking throttle cable. With future diagnosis, this check will be rendered useless.

I've listened for vacuum leaks. Further diagnosis also declines this as being an issue.

After driving the car to the grocery store, the idle really wanted to hang up. I can deal with a 500 rpm hang over standard... that acceptable from a $300 car, but when I'm at a light pushing close to 3K... :saeek:

So I opted to yank the TPS connection...stupid idea in most cases, but again, $300 car.

I drive it home and it runs GREAT! the Idle doesn't spike, the car runs smooth and everything minus the hicckup it has with quick pedal release...

So, if either found that the TPS is indefinately bad, or that by disconnecting it I've limp moded the computer and cloked my real issue.... what are your thoughts? TPS toasted?
 

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Excess TPS voltage is the most common reason for a high idle, and on the TC's they are adjustable. Check between the black and green wires and set it for a little less than 1v(.85-.95 is good). To adj, you should be able to loosen the mounting screws and rotate the TPS. If it won't adj below 1v, then likely the TPS is defective.
 

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Slacks 12 months a year, TCCoAAC Member
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Just as TurboCoupe50 said, I would also guess your TPS is jacked up.Mine has an erratic idle from time to time but I am getting ready to put a 65mm throttle body on it so I am not concerned about it right now.Unless it leaves me stranded along the highway one day.
Chris
 

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Discussion Starter #5
TPS fixed the fast idle... The only running issues I see it having now are its occasional missfire and stumble at idle... When its cold out it wants to miss a little. I don't think there has been a tune up on the car since 1997, let alone an oil change.....

Gunna tackle the oil sending unit cleaning and oil change saturday morning before work...
 

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Slacks 12 months a year, TCCoAAC Member
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2,530 Posts
This may sound stupid but make sure you get Ford Orginal parts when you do the tune up.I didnt believe that when I did my tune up and a few weeks later it started to miss and all, I went to Ford and bought Ford wires, cap, rotor and a Ford TFI and it solved the problem.So instead of spending a little money and a litttle work now, its best to spend a few dollars extra and only do it once.
Thanks,
Chris
 
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