intake gasket leak

ok so let me give u the story so everyone can give the most accurate advice. i replaced my exhaust manifold onmy 97 XJ with the 4.0L back in either august or september with a Banks torque tube. while putting the intake manifold back on i ripped the intake/exhasut gasket on the #5 cylinder intake port. it ripped on the bottom side so i had no idea. a mechaninc told me a while back about it when he tested the vacuum of the intake manifold. my question is am i doin any damage to the engine by leaving it like this? i plan to fix it when i put on a newer 99-present intake manifold but i have been waiting until i have some time becuz i drive it mon.-thurs. on a 30 mile commute to college. i know im probably gettin poor performance and bad gas-mileage from leavin it like this but am i doin any damage? also any tips for doin the swap to the new manifold would be helpful. oh and i would just like to say Royal Purple engine oil and gear oil are definately worth the money i really did get better gas mileage i went from 13.2 average city to 15.1 so i highly reccomend Royal Purple products. another thing thats pretty cool about the gear oil is that it already comes with the limited slip additive already in it

Running with an intake leak on one cylinder can burn a valve. It causes that cylinder to run lean and overheat.

how hard is to change the gasket any tips

If you did the exhaust manifold you can do the intake. it's pretty much the same process. Just make sure you label everything you unplug from the intake, especially vacuum hoses and injector wires. Might be a wise thing to take some digital photos too.
Make sure you use a torque wrench.

Sorry I didn’t explain I have a 99 but i am having some high idle problems and i think is the manifold gasket and i want to replace it

http://autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/15/21/36/0900823d80152136.jsp
There you go.
Sorry about that first link, that was for the grands.
You'll need to go to the right and choose "combination manifold" to get the instructions for a 4.0, it won't let me link directly to it.
Like I said, make sure you use a torque wrench, 23 Ft Lb's isn't a whole lot, you can easily over tighten those bolts. be sure to follow the proper torque sequence.

thanks for the link