I took my 95 LS in to get a miss diagnosed and the mechanic hooked the code reader thing up to her and couldn't get any thing at all.The truck's system would'nt read anything at all even though the check engine light is on.Any ideas?I have to run it without the over drive on and in power mode just to get some drivablity.So something is without doubt amiss(no pun intended!)

1995 Montero LS, KYBs, Michelin 31s. 2009 Kia Borrego EX. (Wife's wheels.)