I recently noticed that MPG have dropped off by almost 5-7. No light on the dash. No loss of performance (at least none that I can notice). Recently changed all the filters. There is some VERY minor "oil leak" near return air manifold (EGR stff?) that loops back on the driver side.
Tire pressure is okay, no fuel leak of any sort. Will appreciate any pointers/suggestions. I did change the brand of diesel fuel as well. Thanks in advance.
Most likely a combination of winter fuel and more cold starts. If you have a lot of miles on it and poor oil change intervals it is possible that the timing chain is wearing, but that would happen ever-so-slowly.
Parot-of-doom: there is no lambda sensor on the diesels. They always run a lean exhaust. Perhaps you meant the air mass sensor (on the intake). Failure of that part leads to a dramatic loss of power.
I have been driving diesels since 1989 ... Winter blend (Kerosene) has rarely messed-up MPG and neither has cold start. As a matter of fact, diesels (all IC engines for that matter) run much better (efficient) in cold weather (denser air mass) than in summer.
Oil changes have been like a clock work @ 3k. Like I said, the only abnormality that I have observed is a very tiny oil leak that is near a sensor on return air manifold (?). Again, thank you all for suggestions/ideas. It is much appreciated.
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