hymer

can anyone give me some help diagnosing a p1391 and a p1698 error codes,on a 97 sport 4.0 ,my tach bounces all over and the motor revs up and its misfiring,ive changed the cam sensor in the distributor,no change, checked the wiring....it starts right up and doesnt sound like it has jumped timing..when i try to go to live data on my code reader with it running,it will start showing engine speed etc.. then it will say lost connection but i can shut the motor off and it will read the codes and clear them no prob??any help would be appr