time out ppl.
what are you trying to fix? Is the car running like crap? You can go to autozone and find breather caps that fits the existing PCV and then get a rubber cap for the port on the intake tube. I ran my car like that for years.
Sounds like the tune is for a 00-04 and not a 97. Unless you didnt hook up those connectors, you shouldnt be getting those odd codes. Or someone forgot to plug in your o2 sensors.
If you have e85 in your area, slapping on a blower with a tune will net you 500hp easily. The stock crank is a beast in these cars and wont need replaced until ike the 750hp range. Your entire setup with a blower would need a good tune.
Both the engine and trans should be fine if they were maintained correctly. 100k is nothing to 4.6 engines. The trannies cant handle a ton of power but they never really had issues other than bent shift forks due to bad shifts.