Expert: Roland Finston - 12/21/2011

Question
QUESTION: We have a 01 Chrysler Sebring coupe lxi. It is running rough, we have replaced sensor after sensor per the mechanic. We also replaced the water pump and timing belt. My husband thinks he found out what is going on, There is another piece attached to the throttle body by a hose. We believe it might show up as a sensor, but it is like a vacuum that moves the throttle. Its located on the wheel well. We have taken it to 3 differ car parts places one being a junk yard and no one can tall us what it is.. My husband sucked in on the hose and it moved the throttle.. Please tell me you know what the name of this piece is.. Thanks in advance!!

ANSWER: Hi Nicole,
Let me check my manual and see what that might be. I'll be back shortly.
Roland

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QUESTION: Thank you so much.. We have already put about $800 in this car trying to fix this issue .

ANSWER: Hi Nicole,
The only vacuum-operated device that it related to the throttle movement that I can identify is the automatic cruise-control 'link' which has a vacuum hose attached to it, and then from the link there is a mechanical cable connection to the throttle lever. It also has a mechanical connection to the accelerator pedal. Sucking on the vacuum hose to the 'link' might well cause some movement of the throttle lever. But that system wouldn't be called into play unless you asked for cruise control.
I doubt that cruise control system would by itself cause rough running except if there were a leak in the vacuum system (the hoses you can trace backward through a vacuum reservoir and from there back to the engine intake manifold, associated with the speed control system and also the power brake system which is also vacuum-operated). But a vacuum leak can cause rough running should there be such a leak. There are many other similar vacuum hoses that could also be checked for cracks/loose fittings.
Have you tried to get any fault codes from the powertrain controlled memory? You turn the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to see it flash, pause, flash, etc.
Count the number of flashes before each pause. Then repeat the process to be sure of an repeatable/accurate set of flash counts. Let me know the results to see if there might be something else that the computer has identified as the cause of the roughness. Also describe what you mean by roughness: when you start it, when it is warm and idling, when you are accelterating, slowing down, cruising at a constant speed, or?
You can also get a more elaborate fault code readout at the mechanic (have you asked for such?) or for free at many nationwide autoparts stores such as Autozone. Let me know any 4-digit number that come from that approach.
Roland
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QUESTION: We have run the codes many times.. We have also reset the system by disconnecting the battery.. No codes are coming up. We also did a tune up including plugs and wires.. Just not understanding what is going on.. Our car was in the mechanics shop for over a month. Trying to fix this issue.. It used to stall when stopping at lights.  It doesn't do that anymore. It also used to act overheated. The temp gauge would read hot as soon as you started the car.. We fixed that.. He also replaced the erg valve and sensor a little while back. If you have any other ideas please let me know. Thanks for helping.

Answer
It appears that you have addressed the common possible causes. Again, what is exactly the issue with 'roughness'? I can't believe that a rough running engine won't cause some sort of fault code to be set. Try to get the free code readout at a nationwide parts store, and try the ignition key on-off routine as we need to get some indication from the engine control module.
Roland
PS: Please 'rate' my answer. Thank you