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idleing problems

12-15-2008, 04:58 PM
When i start my 99 neon it idles fine at 600-700 rpm...than after it warms up it starts to run high at 1100 rpms...and if i get on it real hard it will idle at 2200 rpm any ideas to what that could be????

12-15-2008, 05:02 PM
have you tried putting a new tps sensor on that? and check all vaccum hoses?

12-15-2008, 05:22 PM
havent tired the new tps sensor but for the vacum shit its so messed up under the hood i dont even know what goes to what....it was a mangled mess when got it

12-16-2008, 04:38 PM
I would also suspect a bad Idle Air Control Valve (IACV) and/or bad hoses between the PCV valve on the intake manifold and the camshaft cover. Also maybe a sticking throttle valve - due to a buildup of crud inside the intake manifold.
If you do a google search for "+neon +engine", and select the 'images' search instead of the 'web' search, you will get some pictures of typical Neon engines, some of which will allow you to link over to a Neon forum.
I bought a mopar manual for our 97 Neon on ebay that paid for itself in the first weekend. (Later I removed and replaced the motor, so even more savings due to that manual).
You havent said if your Neon is a single overhead cam or a double - but they are fairly similar.
I replaced the IACV in ours because it was letting the car die when the throttle was shut. The car had about 130,000 miles on it. I removed the whole throttle body to replace it, and even then it was hard to get the little bolts to loosen, and replaced the TPS at the same time - just for the peace of mind. I used plenty of penetrating oil.

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