rough idle

[C280 JR]

OK, this is starting to happen more and more over past couple months...when i sit at the light my car would jerk forward. The idle would go from 600 to 700. It does not go high up to 1K+ as it did when i had a misfire cause of a spark plug. During standing the car would jerk every mabie 20-30 seconds, now it does it pritty much every 5-10 seconds and it gets anoying, im guessing it could be the mass, but im not sure, is there a way i can do something about it to fix it temporarily cause i got a guy claiming he wants to buy my car, and i dont want to shell out any more money on the car!

Elvir

[jnolte]

wire harness
maf
spark plugs
o2 sensors


temporary fix?? elvir your a punk..

[greekC]

check the coils.

[C280 JR]

where is that located?

Elvir

[714guy]

Originally posted by C280 JR
where is that located?

Elvir

the coils are the things that the spark plugs are atached too. You'll have three of them. Also check out the boots that connet the coils to the plugss.

Do you have a scanner?? if not get one and try to see what the problem is so you can concentrate in one area instead of trying to fix a bunch of stuff, b/c rought idles can be caused by a lot of stuff.

[C280 JR]

you think scanner will work without CEL?

Elvir

[C280 JR]

ok i noticed something, when they AC is on the car tends to do this often, and when its off, mostly it does not do it, but when it does its so light its very very hard to notice, probably could not even notice if music is on...any ideas now?

Elvir

[C280 JR]

any ideas? Experiences?

Elvir

[Rocket]

Man, changing my fuel filter made a world of difference. My car runs awesome now!

[C280 JR]

also, forgot to mention, sometimes, the car would choke too, now i dont know if this could be assoiciated with the rattling from the exhaust, cause it chocked several times and poped under the car

Elvir

[Rocket]

You are getting cylinder misfires... Really bad... If you don't do something ASAP if that's a no go get the coils checked then the plug wires. it's going to mess your cat up. Replace the plugs ASAP. Don't use anything but the Bosch Copper plugs from the dealer.


Originally posted by C280 JR
also, forgot to mention, sometimes, the car would choke too, now i dont know if this could be assoiciated with the rattling from the exhaust, cause it chocked several times and poped under the car

Elvir

[alhacker]

check ur coils first, change ur plugs check ur O2 sensor ( metal brush it if u fing black stuff on it ). if all that doesnt work try cleaning the maf sensor... if ur spark plugs have black strikes on the top part its probably ur coils...

[C280 JR]

ok im gonna check into that too, im in school right now so i cannot do it at the moment, but to clarify a little more on what is happening...i dont know if this is related at all.

Recently i noticed that my exhaust made a rattling noise, as if something broke off inside of it, i cannot pin point it where its coming from as it sounds like it echoes. it happened several times not every time, as im turning a left, when i apply gas to turn, it would chocke half way thru the curve, i would hear a pop from under the chasae of the car, meaning its coming form the exhaust then the car would continue..form what i can remember it happened 3 times that noticed probably more than that..

Now another thing that happened is my idle, these pasat couple days i have not noticed it as much as before but what happens is it jums very fast from 600-700rmp, and jerks the car forward...i thikn i also noticed is that it happens when i have A/C more than when i dont cause when i dont have it on the idle just goes up and down from 600-700 very slowly not jerky..and on top of that several times it happened that when i would apply gas it would choke for a second as if its not getting enough fuel from the start and then it would continue without a problem...now i dont know if that is associated with my exhaut, but i will check all the things stated above...

but the O2 sensor, is teat the piece in the tube above the air filter on the left side of the engine...cause im fonfused between o2 sensor, mas sensor and other sensors that there are!!!!

sorry for the long post!
Elvir

[C280 JR]

quick update,...checked sparks, i know i changed one of the coils so i doubt its that..im about to clean the throttle body see if anything happens there...


Elvir

[alhacker]

the sensor that is in the exausht manifold

[C280 JR]

you know where exactly that is located a pic perhaps, and how hard is it to reach it...thanks

Elvir

[C280 JR]

update: used throttle body and air intake cleaner.. smoothened out the rough idle, which is good, also the car does not choke any more at starts..it does a little while its cold..and the rattling from under is from heat shield

[joes280]

which throttle body cleaner did you use...cause i heard mb's are sensitive to additives....

[C280 JR]

it was called "used throttle body and air intake cleaner" i was scared too cause when this guy old mech was spraying it right into my sensor my ide stlarted jumping from 100 to 3000 rpms...i was like oh man im done, i need to buy a new one..and then the car died...i tried to start it up and it took like 30 seconds..lol....but after it started it was A OK..the idle clamed down comapred to before still not the smoothest idle but it worked fine for me

Elvir