I have an '02 neon with a MTX. Just recently today everytime I put it in neutral the engine starts working hard and goes up to 4000rpms. There is no contact with the gas pedal. When its in gear it runs normal though. So I wouldn't assume that its the throttle body getting stuck. Do you know why this could be happening?

Thanks

 

Maby you TPS (trhottle position sensor)?

 

It Might be Charging the battery....

 

but wouldn't it still be running high RPMs with the car in gear? Im not driving the car btw. A relative has it. She called me with the problem. Maybe its injecting too much fuel and when there is no weight on the engine its just running free?? She said that when she was in 5th gear she felt like she was going to stall.

How would charging the battery make thet RPMs go up?

She just called and said that she let it run for a while and it calmed down. She said the tranny light came on too.

 

its still sounds like the tps, whenin gear it wont go up becuase you are using the throttle and forcable putting it to a certin rpm but when just ideling the tps thinks it needs to be opened up??? as for the tranny light im not sure about that!

 

I met up with some friends who all know a great deal about cars. 2 of them have built engines from the block.

When I got the car in my hands they were there for the first start up. Before I started I checked all the sensors that I have messed with. None were loose but i gave them a little push-n-wiggle to make sure. I started up the car in neutral. Nothing happened at all. The I saw the engine light go off as well. I revved it up to about 5000 RPMs and everytime it came back to about 800RPMs just fine. They didn't witness anything and while I was driving it the car was fine. I should also mention that a good driver was driving it before me and he also had the problem as the girl that had intially encountered the problem.

It is gone for now. the friends that I mentioned at the beginning of this said they have all had this problem. They said its just something that happens in the cold(it was 5 degrees outside). They also said it especially will happen when you have a bigger intake system installed.

What do you guys think? Thanks again