'97 LeSabre miss

My girlfriend has a beautiful low mileage Lesabre that I noticed while driving and accelerating from about 40- and up has a slight miss feeling. The car otherwise runs great, idles great etc. She has 72,000 miles and has the original plugs and wires (8 years old). I have replaced last year the p.c.v. and cleaned the throttle body, replaced fuel filter. I was told these original plugs are something special and suppose to go 100,000 miles. What makes them special and so expensive to replace? Does anybody think that I should replace them (and wires?) with same type or go to a lesser price but good quality plug? Maybe professional fuel injector cleaning should also be done? Let me know. Thanks, Formzy

Replace the plugs and wires, way overdue, use oe type ac plugs and high quality wires. They are double platinum and the only ones that will perform and last.

Some people suggest Delco wires or exact equivalent (I used NAPA) wires. I changed mine out about 70K along with the plugs. No use damaging the electronic ignition with bad wires and high gap plugs.

You might check on changing the trans fluid and filter if they've never been changed. Change the Dexcool every two years.

I changed plugs and wires and still have a slight"bog" or flat spot during higher speed conditions such as freeway driving. Any ideas?

Change the fuel filter, scan it for proper 02 operation and tps operation, migh try some injector cleaner like Chevron techron.