E320 poor/rough Idle Problem
I have checked combustion at cylinders and computer shows everything is ok. Spark plugs are new, injectors recently cleaned, and there is no significant error in the scanner that could give a hint. The only error was catalytic sensors and I changed all four of them which obviously didn't help.
When I shift gears from N to D or R transition is very smooth and shaking doesn't gow away or lessen in N compared to D. So problem doesn't look like to be engine or transmission mounts to me.
What else could cause poor/rough idling problem?
EGR? throttle body? which other parts or sensors?
Please advise,
Orkhan
Last edited by Orkhan Mammadov; Jan 7, 2019 at 06:32 AM.
Changed engine and transmission mounts, smooth as silk. The old mounts had collapsed and were very stiff, they were not loose at all when I revved the engine with my foot on the brake in drive so that's why I didn't think it was that, but it was. From what I've read they are prone to failure. Just go ahead and change them, they are the most likely culprit of your issue.
Last edited by charlesb2003; Jan 18, 2019 at 08:43 PM.
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2) Catalyst sensors? I'm going to assume you mean O2 sensors, and if you changed all four, to no avail, you might have plugged up converters, which sill get worse over time, until they cause misfire codes and throw you into limp mode.
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Broadly speaking, you can easily decide if the issue is the engine itself or the mounts in the following manner. First of all, does the needle on RPM occasionally dip at all, even slightly, at idle? Next, with car idling in "Park," place your ear close to each tailpipe. Does the putter of the engine sound perfectly smooth? Up to one sputter/misfire every ten seconds is exceptable, more are not. Lastly, place your hands firmly on the plastic cowling of the engine at idle and feel for any intermittent shake of the engine. Any of these indicators will point to a misfiring engine that will cause a perceivable shaking; the absence of any misfire points to engine/transmission mounts.










