2002 high revs on startup

[FrankDav]

This problem has been slowly building on my 2002 Thunderbird. When I start the car, and it happens when the engine is cold or hot, the engine revs in a split second to 2000 rpms. When cold it slowly drops to 1500 rpms then slowly to 1000 rpms. AS it warms up it reaches a nice 700 rpm idle. When hot it goes to 2000 rpms then drops to 1000 then to 700.
I cleaned the throttle body. It wasn't too dirty so I didn't remove it. I removed the air intake valve and it was pretty black on the inside. I cleaned it to new condition and installed it with a new gasket. There was no change. It still takes off like a jet. This can't be good for the engine.
I'm wondering if the air intake valve might be bad but I didn't want to spend $125 on a new one before I tried to get some mechanic advice here.
This is my first post here. I bought my Tbird about 3 years ago.

 

[biddle]

Since we are an all Ford Thunderbird site, you can omit the make/model of the car from your future post subject to shorten the title. I updated it.

 

[medurham]

This problem has been slowly building on my 2002 Thunderbird. When I start the car, and it happens when the engine is cold or hot, the engine revs in a split second to 2000 rpms. When cold it slowly drops to 1500 rpms then slowly to 1000 rpms. AS it warms up it reaches a nice 700 rpm idle. When hot it goes to 2000 rpms then drops to 1000 then to 700.
I cleaned the throttle body. It wasn't too dirty so I didn't remove it. I removed the air intake valve and it was pretty black on the inside. I cleaned it to new condition and installed it with a new gasket. There was no change. It still takes off like a jet. This can't be good for the engine.
I'm wondering if the air intake valve might be bad but I didn't want to spend $125 on a new one before I tried to get some mechanic advice here.
This is my first post here. I bought my Tbird about 3 years ago.

My 2002 69K mils does something similar. At this point, since it only goes to 1500, I have been putting it in gear and going. But if left in park it does get to the 700-800 rpm after 10-15 seconds. Since my oil light goes out almost immediately, I'm not too fussed about it but if there is an issue I want to know. So I will be watching this thread.

 

[cedarbird2]

My 2003 has been doing that for five years. I wait till it drops to 900 be for putting it into gear

 

[Frankie the Fink]

My 2002 has done the same since I bought it 3 years ago with 18,000 miles on it....
I'm not sure it isn't completely normal and controlled by the computer.

 

[medurham]

My 2003 has been doing that for five years. I wait till it drops to 900 be for putting it into gear

Yes I've been waiting till it gets below 900 rpm also. Its like it revs then the computer takes a reading and then controls, but it never seems to be heading uncontrolled above the 1500 or so mine does.. For me its a non issue, however, I am in the middle of changing valve cover gaskets as 2 plugs were found wet, new plugs and coils, we'll see what it does after that.

 

[edward301]

I went out and started both of my 2002 Birds. Both reved up to 1500 rpm stayed there for about 15 seconds,
then settled down to 1000 rpm. After one minute the revs slowly dropped down to about 800 rpm.

 

[FrankDav]

Well I thank all of you for your replies. From your post It seem to me that revving up tp 1500 rpms seems normal on a cold start then slowly going down to 900 and up to 1500 then return to 900 quickly for a hot start.
A couple of you say yours does the same thing as mine.
I probably should have also told you that I have recently installed a Borla exhaust system that really intensifies the "taking off like a jet" effect.
Well I guess It's not hurting anything but I wish it you only rev to 1500,

 

[Paul Kethman]

This is very normal on all ford v8s of this era. The software holds the rpm high while the O2 sensors are warming up. The feedback loop for the fuel injection/air fuel ratio requires the sensors to be in the proper parameters