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Terrible MPGs After Short Block Replacement, Normal?


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Hello Everyone,

 

Most of you probably know the saga of my short block replacement over the last few months on my 14 Forester N/A.  I finally got a good one, it now has 3000 miles on it.  When it was first installed I noticed that the car didn't coast very well and would slow down excessively.  I was told that was normal and would go away with break in.  It didn't really.  Average MPG is about 21 on a usual road trip where it used to be about 27.  Our loaner car (a 2022 Ascent 2.4T) got better fuel economy.  I also noticed that under heavy load, the CVT holds high RPMS even after letting off the gas.  In general RPMS are higher than they used to be (almost constantly around 3k) and will barely maintain 70mph unloaded on flat ground without increasing RPMS.  I feel as though 3,000 relatively hard miles should have broken in the engine just fine.  The car is currently running 0w-20 Amsoil SS.  All other fluids are new within 20k.  Spark plugs were replaced with the new block, airfilter is an AEM DryFlow with about 10k on it.

Is the loss of MPG due to the fact that the rings actually seal?  Seems like it should do better than a 2.4T Ascent....

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