I have a 95 Avenger with about 118k miles on it. For a while now it has had excessive vibration at idle as well as a low rpm, sometimes it goes down to 400 rpm.It accelerates smoothly and I dont have trouble above 1000 rpm.
Ive had a lot of parts replaced, coil block and wires, spark plugs, filter, PCV , EGR , Engine mount,Fuel filter, I even serviced the injectors along with the combustion chamber. The timing is correct, no bad sensors. I understand the engine has some wear on it but I dont think it should be running so horribly at idle. Any help is greatly appreciated.
Its always idling poorly accompanied with excessive vibration. Normally between 400 to 600 rpm. It doesnt correct itself, the only time I notice it doesnt vibrate as much is when I start it first thing in the morning, but after that when I stop at a red light the engine will vibrate and the rpm will be at that range. One more thing, whenever I turn the engine off it doesnt turn off smoothly like any other engine, it makes noise and sputters as it turns off.
I recently put a K&N air filter on it, and had it checked for bad sensors and nothing came up. Ive done a whole lot of maintenance on this car, with the exception of this problem Im having at idle.
Did it have problems before the filter swap? Also when you say you had the sensors checked, what did you do. Just take it in? If they run a test, the sensor won't ALWAYS show up as bad.
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Mod List. Um WAY too many to fit on here. But the engine can handle about 800HP
Sounds like the exact problem my 2000 Sebring is having. I replaced the throttle position sensor (which fixed another idling problem), but it did not correct the low idle issue. The dealer cannot find the problem, just as Darktengu said.
Good luck man....and hopefully one of us will figure this out!
Yeah , it had this problem way before I changed the air filter or anything else.Its had the vibration ever since I bought it but it got worse when it started getting the low rpm. This happened after I went in to get the timing belt tension adjusted, so I took the car back so they could check the timing and they told me it was good. The guys at Dodge checked the sensors twice and nothing came up, they also recalibrated the computer but I really dont know how that helped. Im trying to figure out if its a problem I can fix on my own or if I should take it to a repair station. The main thing Im urged to fix is the vibration cause it eventually loosens up all the accessory belts and itll screw everything up. Today I read something in the repair manual about an idle air vent passage causing low engine speed, could that be the cause?
Your "idle air vent passage" is opened and closed by Idle Air Contol Valve or IAC Motor.
When you let your foot completely off the gas pedal, the throttle body closes off the main passage completely leaving the engine with no air flow. As soon as the computer detects the speed of the engine at or below normal idle rpm, it opens the "idle air vent passage" by retracting the plunger on the IAC Valve. It continues to retract and extended the plunger in order to keep the engine running at the desired rpm.
Recently my car had the same symptoms as yours. Over the last two months it would periodically throw a code saying the Throttle Position Sensor output was too low or high. I replaced the TPS twice and it didn't change a thing. My car would vibrate and idle down low enough for the low oil pressure light to come on. I replaced the IAC and have not had any problems.
They are not cheap. I would suggest shopping around before buying one. If at all posible, stay away from a Wells brand.
I've got a new Borg-Warner for $53 + shipping if you need it. Hope I was some help.
« Last Edit: February 17, 2006, 04:51:26 AM by Derek »
Hopefully the IAC will take care of the problem. I am interested in buying it from you, you can contact me at srodriguez54@hotmail.com with more information.
Let us know if this fixes the problem, because my "98" Sebring does the same thing. Just a thought; although I think that Derek is on to something, when you changed your spark plugs did you have any oil on them. If so you could try changing your valve cover gasket and spark plug chamber gaskets.
Actually my spark plugs were fine, they showed normal wear and they didnt seem to show anything abnormal going on. Im going to try to chane the IAC and see if that fixes the problem.
This has been happening to me too lately. It only happens when I put the car in neutral while still moving or right when I come to a complete stop. If I leave the clutch down it doesn't happen. About half the time it will cut off entirely unless I rev it up to about 2000. The rest of the time the tach needle just drops like normal, but keeps going past 1100 all the way down to about 400, sputters, and jerks back up to 1100, usually making my belts squeal as well. Its becoming very annoying at stop lights, everyone thinks I'm trying to race them, when I'm just trying to keep my car running.
Just a thought, I had a similar problem in my Venge and I cleaned the throttle body. Problem went away.
You might try that before buying some expensive parts. Just make sure not to spray the throttle body cleaner into the throttle body. Get a paper towel or a rag and soak it and use that to wipe around the inside of the throttle body. Might help, might not, it did for me though.
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