Originally Posted by B1500ram
So i have recently had a sudden loss in fuel economy, i have an 03' 4.7 and it is sucking fuel like crazy. I usually can expect 300 miles or so to a tank and now i am at around 200. I have ran 2 tanks through, i have a k&n and thought that was dirty. It was but not too much and i gave it a good cleaning. Still having the problem though. Any ideas??!
I have heard maybe PCV valve, or 02 sensor? I have not cleaned the throttle body yet, and i am at 155,000 miles now.
Thanks folks... Brian
I just bought my 2002 4.7L a few days ago and I dont know very much about them yet. But I did ask my friend who is a mechanic for 40 years and owns his own shop now about the Sequential fuel injection system. I asked him if it was expensive to repair if it fails or if it was something that goes wrong often. He informed me that if the sequential fuel injection SFI or SEFI system does fail the car goes into limp mode and simply reverts back to its old form of method of injecting the gas into all the cylanders at the same time. He said I wont notice much of a change if that does happen but I will notice a loss in Gas Mileage.
Also maybe think about infesting in a locking gas cap. Maybe someone is syphoning gas out of your tank at night? 5 Gal gas can multiplied by 15 MPG = 75 less miles you will go on that tank.