Mazda Forum - Mazda Enthusiast Forums - 1992 Mazda Miata Steering wheel vibrations Help!!

Hello All,

I desperatly need your help!
I own a 92 Mazda Miata that has 100K miles on it. Its running great has hardly ever gave me any trouble and has been super reliable. I love my Miata!!!
I started getting vibrations in my steering wheel about a month back. It starts at 65 miles per hour to 75.

Things I have tried:

I have put 4 new refurbished tires on my car.
Had a wheel balance at Goodyear tires.
Bought new schocks for the front.
I took it to a garage just to have them tell me I got flat spots on my tires that Goodyear already ruled out. They supposedly rebalanced the tires. and rotated the front ones to the back.(without my permission and charged me for it claiming it was for the Diaognotic)

When they rotated the tires the vibrations comes up at 40 MPH and at 65 MPH to 75.
So now its worse.:mad:

Im at a loss... Some say it could be a bent rim.. I do have a tiny nickle size dent in one of the rims that has been there for years so I highly doubt thats it...

Any suggestions?
Maybe its time for new spark plugs? Maybe its an engine thing going on?? I am having the spark plugs replaced this weekend so maybe that will help.
I appreciate any suggestions and many thanks!!