I have a stock 1996 XJ and when I am cruising at 45 and up it will not shift down a gear when I push the pedal. It just slowly accelerates in 4th gear even if it is floored. I put on a new TPS and reset the kick down cable. What else can I do get it to downshift into a “passing gear”? Should I jump into changing out the shift solenoids under the transmission oil pan. Anything else I can do?