I recently replaced all 4 of my engine, motor, and trans. mounts. While the car is running better I still have vibration at the stop light. I tried increasing the idle speed while the car is in gear and it did settle down. Has anyone figured out how to increase the idle speed on a Neon. I pulled out the IAC motor and cleaned it. I also shot inside the body and used a small rag to clean up the carbon build up. Everything I have read tells me you cannot manually adjust the idle speed. Thank you......Richard

 

I didn't figure it out; I read it in another forum. I drilled a 1/8" hole in my throttle plate (butterfly) and it improved the idle nicely. The thought of this seems to terrify some people, but it makes sense if you think about it. When you turn the idle adjustment screw, all you're doing is opening the throttle plate to allow more air past it. The problem with that is, since the throttle body has a TPS, the ECM will eventually set the idle back to where it was. Drilling a hole in the throttle plate accomplishes the same thing; it allows more air past it without changing the position of it.

 

Thanks for the info and yea it does sound scary to drill your throttle plate. I guess I can start with a smaller hole and increase it up to 1/8" if need be.

 

I did a 1/16 on mine that did the trick after a few years of constantly cleaning it I drilled one

 

I believe I started with a 1/16 also and then went to up a 1/8 to get it to idle just right. The throttle plate is plastic, so it's easy to drill and if it doesn't work you can always put a little epoxy in the hole to fill it back in.

 

I was just thinking of what I can use to fill the hole if need be. Epoxy should work good. Of all the cars I have had I have done the most jerry rigging on my Neon. Still it takes a licking and keeps on ticking....