less mpg after spark plug change
THE ULTI-MOD
Joined: Jan 2007
Posts: 19,797
Likes: 36
From: Union NJ
if you just put a brand new engine in, that is your problem, they need to break in before they will run at peak efficiency, and the fact that its a 5.9 is another part of the problem, they are NOT easy on gas
Hall Of Fame
Joined: Jun 2005
Posts: 14,228
Likes: 19
From: Riverton, UT
To reset your engine codes:
Remove the negative terminal of your battery (10mm wrench).
Turn your ignition key to START and hold it there for about 15 seconds.
Turn your ignition key to OFF and remove it.
Connect the negative terminal of your battery.
Start but do not hit the throttle. Idle for about 10/15 seconds then turn off.
Restart the truck and drive as usual. It will take at least 12 starts and 48 miles to fully retune the computer. Hard Codes leave a shaddow for 40 full cold starts.
Remove the negative terminal of your battery (10mm wrench).
Turn your ignition key to START and hold it there for about 15 seconds.
Turn your ignition key to OFF and remove it.
Connect the negative terminal of your battery.
Start but do not hit the throttle. Idle for about 10/15 seconds then turn off.
Restart the truck and drive as usual. It will take at least 12 starts and 48 miles to fully retune the computer. Hard Codes leave a shaddow for 40 full cold starts.