This is topic idle problem in forum Tech Talk at Northern California Ford Owners  .


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Posted by shiftylx (Member # 2670) on :
 
i just bought a 90 droptop and it's starting to take a couple of seconds for the RPM's to fall back to normal after i take my foot off the throttle. it happens in every gear and every time now. anyone? [Confused]
 
Posted by SBSkid (Member # 2560) on :
 
I have the same problem every time I push on the clutch the rpm go up then it comes down while driveing. Then at a stop my idle sometimes does goes up and down between 2000rpm and 900. its crazy.
 
Posted by 92coupe (Member # 1957) on :
 
damn this same thing happened to my friend, i cant remember how he fixed it. ill ask him though, but be happy, my car rarely idles at all. [Smile]
 
Posted by Bill/APEX Motorsports (Member # 636) on :
 
As long as the throttle body is clean and isn't sticking open slightly, it could be the idle air bypass valve. On the older cars, we see them dead all the time. That can cause idling problems. Check to see it's working by unplugging it at idle. If the idle drops or the engine stalls, it's working. If nothing happens, it should be replaced. They're only about $38 or so.
It could also be the throttle position sensor. Have you checked voltage? It should be roughly .95 volts.
Then there's always the possibility of a problem with the mass air meter or engine coolant temperature sensor...
There's a whole host of things to look at on older cars such as yours, and it can be frustrating trying to diagnose. Argh... [Mad]

[ April 06, 2003, 10:16 PM: Message edited by: Bill/APEX Motorsports ]
 
Posted by The Nick (Member # 2244) on :
 
My car does it because its still a speed density car and the computer has no idea what is going on with the higher lift cam. Depending on what year your cars are, that could be it.
 
Posted by 347Saleen (Member # 2548) on :
 
my car was tweakin like that and i changes the o2 sensor and it solved it
Just a thought
 
Posted by AcesWild85 (Member # 2616) on :
 
Try pulling your throttlebody and idle air bypass and clean them out with some throttle body cleaner. AMSoil makes this foaming intake cleaner stuff that works really well. You can shoot that stuff into the intake manifold and it breaks up a lot of crap. My car ran soo much better after doing this. I felt a very noticable seat-of-the-pants increase in power after doing this. If you want to go the whole 9 yards, get a bottle of techron (or 2) , and with your engine running, take the black vacuum line from the intake and stick it in the techron and let it drain the bottle(s). Let the car sit atleast over night. Then when you start it up, it will smoke pretty bad, but it will run better once it burns all the s**t off.
 
Posted by shiftylx (Member # 2670) on :
 
is the vacuum line the one underneath the intake?
 
Posted by 87mustang (Member # 2496) on :
 
i was told that its the computer thinking what to do!
 




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