my neon is idling at 4000rpm, like throttle is stuck.. could this be the idle control unit, or the throttle position sensor. No check engine light lit.

 

what do you mean it is idling there. if it is idling there constantly yo have huge problem and shouldnt ever drive that car until its fixed im assuming you mean you cant rev past 4000 in park or neutral which is completely normal and cant be helped

 

it is idling there. also there are no error codes being shown....

 

How did it start doing that? Did you install something and now it is doing this? I would lean towards the TPS.

 

my bet is major is vac leak

 

just started on its own. no altercations. how would i check for vac leaks with the engine idling this high. it would pose a threat to the engine correct?

 

I say you should tow it to a dealership to get it looked at. Under warrantee. THAT or you have to start doing a lot of work!

The only things I see is the MAF sensor or the TPS

I do, like LowSlow lean towards the TPS.

 

just listen for load hiss what that is how I normally find my leaks.
you might want too check if throttle cable is stuck at t/b.

How can bad tps cause this? Don't understand how it could up the cars idle?
It could be the iac motorbut I would check the cheap first.

 

if its a vac leek you wouldnt make it past 4000 but idle would be normal chepest check is to ckeck your throttle spring to make sure it is retuning to idle or is not blocked by anything. then make sure your throttle cabble is able to retract and not jammed

 

i have checked the cable and all seems well. i am completely lost by this one. gotta get it fixed fast though it is my wife's car.