rough idle problem

I have a 2000 Plymouth chrysler 4 cylinder which seems to be having a severe idling problem. It idles rough in neutral but when put in drive or
especially reverse it seems to act as if its chugging. About 2 weeks ago put some of that oil bar leak stuff to help close up a rear oil seal leak. (did that first before having to take the transaxle off) But it lessened the leak but didnt stop it. Anyways a week later, it comes up with this idling problem. Changed spark plugs, which had alot of ash buildup (I assume from the specialized additive oil) still, the same problem. Put a spark tester and tested all spark plug lines, all good. Put some injector cleaner in the tank and still the same. Tried looking for a intake leak with carb cleaner and found none visible. But one weird thing is that I put a vacum pump on the EGR valve while running and the engine did not die or stumble when applied. (changed the EGR valve bout 4 months ago and cleaned out the long tube, it was packed with carbon) Anyone here have an idea what the problem could be?
EdwinT
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On Fri, 4 May 2012 15:25:48 -0500, Ed wrote:

Forgot to mention that there are no OBD II codes. And no check engine light.
EdwinT
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Look, I had a Chrysler V8 behave like that, and it turned out to be slag on the valves. Local mechanic has the machine to clean them and after the job, the unit went on like a champion.
Mine set no codes either.
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On Fri, 4 May 2012 18:43:51 -0500, hls wrote:

yeah was thinking the same thing. That the shit has gooked up on valves and stems. Maybe the stuff isnt really worth putting in for such oil leaks.
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I had never used oil leak compound when this happened. It was simply the effect of motor oil and gasoline deposits on the backsides of the valved.
I would not have believed it, but the treatment was 100% effective.. Might not be the same as yours though.
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I think Ive discovered what might be wrong with the thing. As I noticed that the chugging idle seemed to get worse when put in reverse and not in foward. I started thinking it might not be an idle problem but just be bad motor mounts. As I remember someone telling me that his motor mounts were bad and it caused his car to hard starting,rough idleing (as it seemed like but was really the vibrations) Looked up on Utube and saw how to check for one. Well did the same tests and yes...engine moves consideralbly when moving back and foward. So its gotta be the mounts. I did however forget to mention on the first post that the muffler was vibrating also and that I found that is was banging up and down on the muffler heat shield. So i simply bent the shield a little higher so it wont hit the muffler. Now that I think of it..the moving engine could cause this also. Plus strange noises seem to happen when making turns while gas pedal is suddenly depressed, along with crunching poping sounds from the CV axles (something else someone told me might be a serious motor mount failure)Just gonna change em out for the hell of it.
Ed
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Strange and dangerous things can happen when you have bad motor mounts. I hope you will let us know how this comes out.
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