Re: 4.2 question
If you want to improve the way it runs....then you don't want to remove the vacuum lines...it will only run worse. Contrary to backyard belief, disconnecting all the vacuum lines does not help....in fact, most of the stuff is there to improve driveability......and they do not hurt your performance or gas mileage.....take them all off and it will most likely run worse and spit out more emissions.
For example....the fresh air pulse system. Take off those lines and you will most likely start getting back firing. Leave it on, no back fire and the exhaust is a little cleaner.
No doubt it gets really cold where you live....change things and you can expect your morning warm ups to take a lot longer.....assuming that it starts at all.
Do you like the smell of raw gas? Disconnect the vacuum lines to the charcol canister and you will get plenty of raw gas smell. Leave it hooked up properly and you might get just a slight increase in MPG as you burn off the trapped raw gas. One thing is for sure, it does not take away any power.
About the only item that you can disconnect without serious repercussions is the EGR.....that is if you like the smell of exhaust fumes....