Hello, new to the Cherokee and Jeep world...just bought a 99 XJ 4.0 auto..did a complete tune up using Champion replacement platnum plugs from Autozone and a duralast cap, rotor and wires...engine seems to be running rougher, I had gapped the plugs to .035...the one I took out ranged from 60 to 80...seems to have a very hot exhaust too...when you put your hand near the tailpipe it is puff puff puff and extremely hot exhaust air..not normal warm.. ..any thoughts? car ran smooth before but the parts were brittle and shot when I took them out. Thanks!

 

did you put all your plug wires back in the same spot ? might wanna double check that

 

I marked each one when I did it with a marker butI will check again...does anyone have a firing order diagram? spark plug wire routing?