This could be your problem: friggin' ford does this stuff all the time

[Camshaft Rotational Dampener-
Is your camshaft spinning out of control? Most car manufacturers cut costs and avoid installing this important part. Did you know that expensive camshaft could be spinning at speeds of up to 7500rpm - tearing up the inside of your motor? Symptoms maybe vibration at speed, vibration at idle, and loud noises coming from your exhaust. Install KaleCo rotational dampener to eliminate cam spin!
$100 Each
$175 Set of 2]
They also offer muffler bearings & other hard to find items... Kale Co Auto

1999 Sportage 4x4...don't go there, it was free ....______o_o .../_l l__\____\ ..|--l l__----[]\|/[] .....................oo =( )_)----( )_)--)_)