front end shimmy
 

at 35-45 mph there is a slight vibration in the front passenger area. the car is a 2004 civic lx coupe. i do have aftermarket rims 18" and lowering kit, but this problem just started. please help, and hopefully it's a cheap resolve. i've spent way too much in repairs in the past month, for example warped head, bad egr valve to name a few. 10 miles after rebuilding the top end the check engine light came on and stays on. i've had it checked and the mechanic says to drive it and put miles on it so he can get a code to diagnose. i think i've got a lemon. i bought it less than a month ago and have $3000 in repairs already, now front end is shaking....HELP PLEASE