i have seen the 02 / maf fuse blow on these and cause issues. ive even had to run a new power wire to the maf and the o2. dunno why but after i verify the two sensors didnt have power with a good fuse i ran a jumper and its been over a year. been fine. this was a 97 gt. just an idea. do you have a scanner at all? do these two sensors read they are working?