'94 2.6 breaking rocker arms
 

'94 2.6, bought with a broken rocker arm. swapped an original rocker arm to the affected cylinder for testing and put a new rocker arm on the unaffected cylinder. fast forward a couple of weeks and the new rocker arm breaks. replaced it with another new rocker arm, then a couple of months later another of the original rocker arms on a completely different cylinder breaks. ideas?