Cranky I know this is an older post, but is 96 the first year with the kegger intake?
Chrysler fixed the plenum gasket issue in 99 or 2000. I had to do it on my 98, with only 50k miles on it, because it was acting odd and I had vacuum on both the PCV side and the driver side. Turns out when I got it open it was BAD. Truck ran "fine" before but much better after.
Somewhere in 99/00 they added a second O2 on the front end on the y pipe also. This helped the ECU out, but also made it impossible to do away with a plugged cat or modify the front exhaust without a good deal of $$ also.
My 98 has a single O2 up front, and the back one is there mostly to verify a cat exists. Except the ECU is so basic I zip tied it to the frame rail and it works fine because my cat was plugged 6 ways from Sunday, likely due to the intake issue. And I mean plugged, as in stuff inside rattled around and the housing was actually expanded from the engine forcing the gas through the thing. Not sure how it ran how it did, much less do righteous burnouts in that state. I credit the 318 for it.
To the fellow with the swap, keep the above in mind when you go to figure out you pipes. you need the front O2 for a 98 ECU, AND you need the rear, but 9/10 the rear one is only looking for a different reading then the front one gets so there are ways to save some $$ if you don't need emissions inspections.
from Connecticut.
