Throttle stuck open. GF almost wrecked
 

She called me this evening freaking out. When she left work the throttle stuck wide open and she barely got the car stopped. Went through a red light and got lucky she did not get hit. Said she turned the car off and when she started it back up it was fine. There is nothing on the floorboord for the pedal to get stuck on. I have checked the cables and everything seems fine and to be working like it should. Gonna tear into it in the morning. Any ideas where to look?

Its a 2002 protege 5

Get the throttle body cleaned (it may be full of junk,carbon deposits) and also lubricate the spring where throttle cable is attached to the throttle body(the one that you can operate manualy if under the bonnet mate).If no joy try to scan it and tell us the codes you get.Fingers crossed!!!

I am with escobar. Before you clean disconnect the throttle cable and move the throttle by hand. Maybe you can feel it stick somewhere and youcan tell what the job does. While you have the throttle body off, clean out the EGR orifices at the intake manifold. They are at the 6 o'clock and the 12 o'clock positions.
Check the throttle cable while it is disconnected. Move the end in and out, feel for any "hook-ups". If only one small thread of wire has broken and uncoiled it can make the cable stick and it should be replaced. I lubed my cable with Liquid Wrench oil. Putting a few drops in the cable housing and moving the cable in and out until I could not feel any friction. My throttle did not stick but I didn' like that tiny hook-up I could feel with the foot.
Clean your throttle body inside and outside with a can of throttle body cleaner, nothing else.

Thanks for the info all.

Update.

Over the weekend I called the dealership and they said it could be the IAC valve. I took this apart and cleaned it really good. I also took off the breather hose and checked the butterfly and cleaned around it. Nothing really looked all that dirty. I checked the cable and everything moves freely and I lubed it up pretty good. I never took the cable completely off and looked for burrs or anything. I will do that next.

I also have not taken the complete throttlebody off yet and cleaned inside. Could this really be the cause?

I did take it to Autozone and had them check it on the computer. All it came up with was an oxygen sensor error. She said the check engine light had been on for a couple months before so this may not be related.

This is the belt and suspenders approach: I would take the throttle body off and clean it just to be sure to get any gunk behind the butterfly. It is possible that gunk at the butterfly axle made the throttle stick. That gunk would come from the PCV system and from the EGR system. In somewhat worn engines the EGR carries some engine oil that goes past the rings and valve guides.

I didn't consider that the IAC valve could have caused the trouble. But it does make sense. Most likely the IAC cleaning fixed it. But when it comes to GF's inner peace "most likely" may not cut it.

If your throttle cable moved without friction then you are good there. If there is friction simply replace it.

Now the CEL does not say the O2 sensor is bad. It says that the O2 sensor delivered data which the computer did not like. Get the code number and Google for that code number. It could point to a problem that lead to the sticking of the IAC valve, throttle or EGR system. We will take it from there.