hello everyone. been a while since ive posted anything but i am in need of some assistance. im working on a friends 05 neon 2.0. she is experiencing low rpms while the car is stopped and in drive. now in park or neutral it idles normally. right at 1000 rpm mark. i took it for a test drive and it rides normally. no hesitation when taking off, or anything like that. it just idles low when its at a stop. i would say a hair above the 500 rpm line. it has a bad vibration, almost like the motor it about it shake itself out of the hood lol. she took it to the stealership and they told her that it was a few things that went bad. so before she had them work on it, i told her to let me take a look at it. i went through the engine checking the normal stuff like the iac, evs and tps, pcv, etc. (the parts that they told her were going bad). i also pulled all the vacuum lines and checked them to make sure nothing was clogged. everything was fine. i also played with the adjustment screw on the side of the throttle body to see if that would help any. still no luck. ive been scratching my head over this for a couple days now trying to figure out while it has a low idle and i figure its time for a second set of eyes. if anyone has any ideas on what it could be, they would be helpful. thanks alot

 

Have one person get in the car and shift into drive while holding their left foot FIRMLY on the brake pedal. Pop the hood and have another person observe the movement of the engine when the drive taps the gas with their right foot and lets off quickly. Repeat this process with the reverse gear.

If their is an audible noise or the engine movement is extreme then it is the motor mounts. Check around the mounts for cracking in the rubber.

 

ahh i never even thought about that lol. good idea. i made mention of that to my friend and she said her dad replaced the upper and lower torque strut mount about 4 months ago. right around the time she started experiencing this issue. go figure lol. im going to take a look at my dodge manual and see if the motor was adjusted to specs when the new mounts were put on. might as well take a look at that fender mount as well. ill post back when check it out

 

Yeah, if the procedure for aligning the lower torque strut was not followed correctly you'll experience a terrible vibration.

 

the dodge manual says that the post on the engine mount bracket for the upper torque has to be 4.70 from the center of the hole for the washer hose clip. i measured it and its off by a 1/16th. i dont see why that would make a difference. i cant adjust it any lower without drilling out the hole in the mount to make some play for the bolt.

 

Agreed on the lower (pencil strut as it is called in the manual) replace steering rack and didnt follow procedure nd damn that Vibration till i Figured it out. A;so one neon we had at the stealership had this same problem. REplaced the O2 sensor hasnt come back yet IDK computers are unny sometimes

 

gotcha. ill try that. thanks for the replys

 

For starters, engines drop in RPMs while in gear at a stop. That's normal. As for the vibration, are you positive the actual motor mount is in good condition? The reason I ask, is pretty much the only way to actually tell or not is to either remove it or have the engine not be there. I have a horrible vibration at idle as well, and after seeing every single motor mount being busted on Neons at the junk yard, and hearing story after story about how changing the motor mount eliminated vibrations and squeaks, I always lean towards that first. Crappy design is your answer as to why they go bad so much.

 

Yea I took both of the mounts off last night and brought them into work today and compared them to mounts we have in stock. they are identical. The rubber parts are hard as a rock though. I don't remember them being this solid when I did my mounts a few months ago. As for it being anything else, I went over that car prior to removing anything and checked everything I could and didn't notice anything out of the ordinary.

 

I think most neon's have this issue. I know mine did and there was nothing I could do to fix it. I believe it was a design flaw from dodge. But that is just my opinion.