Rhythmic thump sound @ 20-45ish mph
I have a 2005 E320 2WD withh ~64k miles that has developed a rhythmic "thump" or "thunk" sound that happens around 20-45mph. It almost sounds like you are driving on a highway with the concrete separator gaps spaced evenly and frequently. It can be felt in the steering wheel and gas pedal, and seems to go away as I accelerate past 50mph. In an effort to troubleshoot I replaced the front passenger side wheel (it seemed like this is where it was coming from) with the spare donut tire and it felt like it got worse. I have a call into my mechanic but was wondering if any of you have an idea as to what it may be. Initially I thought I bent a wheel or had an out of round tire but after the spare tire experiment I am wondering if its something suspension related. Just as an FYI my mechanical skills go as far as doing a brake job or replacing an alternator. Anything beyond that, I know enough to be dangerous but not all that helpful.
Any ideas? Thanks in advance.
Easily the simplest and cheapest thing to check first.



