I'm not sure what might be the problem but the last 20k miles or so I have had some wicked vibrations while my car has been idling and recently as I begin to accelerate, I'm getting a steady vibration (almost like a stutter). My vehicle has just hit 90k miles and I had an engine replacement @ 68k miles (mazda replaced engine under warranty). Could this be a catalytic converter problem or am I looking at something more serious than this? I have no check engine light on at this time.

 

Thanks for creating a new thread

Anyway, check the engine mounts, they are notorious for tearing/cracking etc after significant number of miles

 

well Mazda replaced my engine 1 year ago so I would assume that they would have replaced any engine mounts that were no good.

 

I'll be honest with you... you'd be surprised at the half assed job a lot of dealerships do.

 

Motor mounts are only covered under Bumper to Bumper warranty, and not covered under Powertrain or Engine core warranties. If you didn't get charged for the replacement, they didn't do it.

 

Thanks guys I appreciate the info, I'll look into it after work. If it were just the engine mounts though would I be feeling vibrations only at the low RPM's and I see my RPM gauge waiver as I'm sitting at Idle, it typically idles below 1000 and bounces back between 800 and 1000 while idling, it that normal?

 

Engine mount failure won't cause an idle change, JUST engine mounts would be a steady idle with heavy vibration.

If your idle isn't stable, you probably have a vacuum leak, fouled MAF, and/or a failing front O2 sensor.