Thread: Strange vibration/pulse. Powertrain or suspension?

could be the motor and trans mounts.

pop the hood and then shift it to reverse and see if the engine moves a lot, try to check it when the engine is cold, in the morning so the idle is higher.

I just drove this thing 220 miles round trip (face-palm I know, but I had no choice, we've all been there).

I had to keep it at 55 or 60 on both 110 mile legs of my drive. First I drove at 70-75 because the vibration seemed to disappear completely at higher RPM, until the car got pissed and I could tell that if I pushed it something was going to give. Any bump or disturbance in the road exacerbated the problem.

It got worse whenever I was decelerating, so I used the cruise control and my foot rested against the gas pedal to make sure that even a deceleration of 5mph took about 10 seconds. Acceleration seemed to sometimes minimize the vibration, but it did not eliminate it, so it's definitely worst when I'm letting off the throttle.

When I got off the highway after 220 miles of driving, the engine idled fine, shifted great, and the vibration was about half of what it was on the highway. Even at city speeds the shuddering/vibration is consistent with acceleration/deceleration. When I'm holding steady speed (whether it be 25 or 65 mph) the vibration isn't as bad. I held my ear to all corners of the engine bay and listened to the idle, no noises to be heard.

Any advice? What should I check? If I do replace the mounts is there certain brand or type of mount that is best?

Sounds like you have a wheel out of balance to me. I had the same condition, It started after I rotated my tires, ended up tossing on another wheel and it went away.