My wife’s 2001 4.7L Durango has about 188k on it. As of a year or 2 ago, the mpg has dropped from 18ish to 14ish mpg. Plugs, coils and viscous fan clutch have been replaced. Clean K&N filter and oil changed regularly. Engine seems to pull and accelerate without problem. Would think about injectors but hesitant due to expense and the fact it seems to be running fine other than the drop in mpg. Air, spark and fuel are the basics but I’m also wondering if something else wearing in the drive train or motor can can cause this.
Trying to adhere to the C&C rule that the best value in a vehicle is to drive it into the ground, without chasing ghosts that aren’t there.
A tired oxygen sensor can drop your mileage long before it sets a code. I don’t know if there is a way to test them, maybe someone will enlighten us both.
Another quick way to reduce fuel mileage is low tire pressure. The vehicle will run great and handle normally. Check your tire pressure. I have used 32psi as a tire pressure in every vehicle I have ever owned. I always get great gas mileage and tire wear.
I should have mentioned that I’m on top of the tire pressure as well.
Hmm. hadn’t thought of the o2 sensor. I’ll have to do a little more research on it.