More Flexplate Issues/maybe More

It Started With A Light To A More Progressive Squeaking From The Trans Region. I Can Only Determine It Was That Area Because The Sound Is Only When I Am Driving/on Throttle. There Are Some Days There Is None Of The Squeaking At All. When Started In The Morning,it Lags Really Bad,i Give It Gas,nothing,then It Kicks In. Recently My Check Engine Light Goes On,then Off. The Sound All Together Has Gotten Worse. My Cks Is New. Any Advice Would Help So I Know For Sure What Parts I Need To Order To Get The Jeep Fixed. Thanks.

What year/engine/drivetrain?

I'd suspect Ujoints first.

Check engine light could be many things, might I suggest going to AutoZone or similar and have them plug it into a diagnostic? If your CE light is on, they will do it for free.

Now that was intelligent!!!

What Could The Fault Be In The U-joints To Cause Such A Bad Squeaking? I Have Already Received My Flexplate From The Dealership...got A Good Price Too($62.50) Even With The Shipping To Hawaii. The Year Make Model Of My Xj Is 99 Cherokee Sport 4wd,4.0 I6. 6.5" Rough Lift W/33" Pro Comp All Terrains.m.o.r.e Bomb Proof Motor Mounts,skyjacker Soft-ride Leafs......and Then Some.

to isolate the flexplate, put the vehicle in gear hold the brakes, putting load on the engine will torque the flexplate and make noise if it's cracked