Automatic trans.  4.0 i6. It currently has about 129k miles.  

When I got it it had highway tires and it got 22mpg on the freeway.  I changed the tires to a moderatly aggressive tread. And I got 19mpg on the freeway.  Ok tire changes will do that.   Then after a few gasoline smelling days I had to replace the fuel pressure regulator thingy and fuel filter.  Long story shortened I currently get about 13 to 15 mpg when running top grade gas and mostly driving around town.  😳

Besides the mpg issues... Sometimes when I start it and start to go. It stutters and dies.  It always starts again and acts generally normal but that is just annoying.  Hints? Btw it did this before the fpr and fuel filter change too.  

I love this Jeep and do not want the plastic and electronic crap in modern cars at all.  If i could i would go back in time and keep my 58 studebaker silver hawk.  

Ok second issue is the speedo went nuts as in bouncing around going from zero then wento to 108 and back to 80.  I had the speed sensor changed with a new one, no joy.  I replaced the board on the back of the Speedo... Now speedo and oil guage won't work.  😆.  

I would really appreciate some good help.  I am a 60 yo widow so the more detail the better.  Thanks in advance.