mpg drop, ideas?
#1
#5
#6
ok, so i redid the plugs within the last 10k miles they where champion coppers , didn't mess with the wires honestly, i looked into the cap n rotor and while i was contemplating upgrading it dad just sanded the old stuff off and it was reassembled, i put a k&n air filter in there and it increased my mpg from 15 to 17 before the sudden drop., my cousin says it could be a dirty throttle body, i didnt think the o2 sensors could have that much affect on a truck that old, but I'll check it out, and i also think the good ol catalytic converter could be on death row.
#7
Look for oil in the intake. The plenum gasket may have blown. There is a TSB on it. If you go the regular repair route it will happen again but its 200K so????? Hughes Engines makes a permanent repair kit with a 1/4 aluminum plenum replacement for the factory steel plate which is the cause of the problem. Get new intake bolts if you do that. My mileage has gone from 9mpgs to 17+ I also did all new sensors including EGR and O2 and wires cap rotor coil and switch plate.
Last edited by onemore94dak; 10-21-2014 at 08:33 PM.