Rpm Stay Stuck?

[Taino]

I got a 90 5.0 .... So Im cruising down the turnpike doing about 75-80mph, I let off the gas and the RPM are staying over 2600 rpms.?... I pull over turn off the car start it up and all is well. After about 5 minutes doing about 80 MPH again I let off the gas and the RPMs are still going. I pull on the gas pedal just to see if it lowers the RPMs but no still at 2600? Advise, I've replaced the IAC, Have to check TPS or its simply time to change out the throttle body, Its still the OEM one from 22 yrs ago. Have no clue on what to look at beyond that? Any advise ?

 

[Jace78]

Stuck tachometer or is the engine actually staying revved?

 

[MFE92]

Time to clean/tweak the 10-pin connectors.

 

[Taino]

The engine is actually staying revved. I had heard about the 10pin connector. Have to research it. Lets see if there is a sticky here I can use to get info on it ? can anyone lead me to where i can get more info on this?

 

[StangGT1995]

Any codes? Does it rev freely? Throttle cable isn't binding is it?

 

[Taino]

Cant be cable binding, I turned of the car and restarted it in motion and the RPM went back to normal. If cable was binding it wouldnt go back to normal. Sorry,
as easy as many say it is to get codes I simple don't get it other than getting a code scanner unit.

 

[StangGT1995]

You can pull codes with a paperclip and by watching the check engine light flash on your dash.

 

[Taino]

Tried it, as easy as everyone makes it sounds i cant get it to work. never the less, that option is OUT! I"ll figure it out thanks anyways

 

[madspeed]

stuck throttle body!

 

[f8tlfiveo]

My bro had a similar prob... He had a bit of gunk in the tb.. The blade wasn't closing all the way all the time.. I would say take a look at that.

 

[madspeed]

pull off the intake pipe and you can see the tb blade. you can push it open by hand and wipe it all out. if real bad, spray a little cleaner in there

 

[89stang1]

i bought this code scanner off Amazon it gives you the code number easy to use!....... definitly the best 25 bucks i have spent on car
http://www.amazon.com/dp/B000EW0KHW/?tag=stangnet-20

 

[madspeed]

forgot about that, i have one as well!! Highly recomend it. Read the instructions, as its a little confusing at first will all the koeo koer stuff it can do

 

[Taino]

So A buddy at work brought his code scanner in and we started to plug it in to get a reading. There is a pig tail for a 4 prong unit which I found right away and plugged into scanner. The scanner requires a second single prong pigtail to be plugged in but its nowhere to be found ??????

 

[madspeed]

should be right between the brake booster and fender. the single has a grey plastic fitting on it

 

[Taino]

Followed the wireing harness for the 4 prong connector, that single wire must be coming from another area in the harmess cause I could not find it. Will post pictures when I get home for better reference. Remeber, it a 1990 Gt just in case things are diff. You never know?

 

[Taino]

Ok so this what i found. My left hand it touching a single wire, the other connector into the back of the scanner is located to the Right on the opposite end of the shock absorber tower????? This cant be the cable ..... or is it ?

 

[madspeed]

yes, thats it!

 

[Taino]

WTH, URGH! They need to fire the guy who did this. Ok so this single test connector wire has 2 wires coming out of it, Black wire, white stripe. Don't want to start hacking away at insulation and find out thats not the wire!

 

[madspeed]

hang on....look behind the strut tower. there should be a single connector like that there