Decreasing Fuel Mileage

[rumpledoll]

A few bad batches of gasoline with a substandard additive package may have put some gunk on the fuel injectors, intake valve backsides and caused combustion chamber deposits. These three items can cause both a fuel economy loss and a power loss as the engine runs richer than needed and adjusts the spark timing to compensate.

Surprisingly in this day and age of ripoff products and snake oil, there are simple, cheap and effective products to remove virtually all these deposits - those fuel cleaners that one adds to the gas tank.

Like so many things, some of them are better than others. What one wants are the gas cleaners that have PolyEther Amines (PEA). Sometimes there are other cleaners as well, but it must have a significant PEA fraction in it. Unfortunately the bottles on the shelf don't tell you what they have! One has to look at the Material Safety Data Sheets (MSDS) that every manufacturer must provide - many are conveniently on the web.

To cut to the recommendations:

Best category:

Red Line SI-1
Amsoil Pi

Both have plenty of PEA and a few other cleaners in them

Good category:

Gumout Regane Complete Also has plenty of PEA but no other cleaners (note - many Gumout products have no PEA in them, the Regane does for sure as does their large vehicle fuel system cleaner)

There are most likely others that have PEA in them, but the 3 above do for sure. Gumout Regane is available at many outlets and I picked up some Red Line SI-1 at Pep Boys. Amsoil Pi is available from an Amsoil dealer, or off the web.

Note on Techron: For a long time Techron advertised as having PEA in it. However, the MSDS for the Techron Concentrate Plus now shows no PEA in the formula. The Bulk gas additive also named Techron which is used in Texaco and Chevron gas *does* still list PEA in it's MSDS. So, the gas from Texaco and Chevron has a good additive package, but the bottle of Techron one can buy is not as good as those with PEA.

Rumple

Originally Posted by rthomasf

...my MPG has dropped from 48-49 irrespective of the season (I live in Florida) to 39-40. The decline has been gradual, and it continues.

[LS5099]

Any thought that you might have a battery cell(s) going bad? Loss of storage capacity would result in continued downward MPG.

[greenjack]

You're not alone. I recently bought an '05 and the mileage sucks compared to my '08 (yes, I have two Priuses). The '05 is getting the low 40s while my '08 is in the low 50s. Quite significant. The dealer couldn't seem to locate a problem with the '05. Funny thing is I'm driving both vehicles the same. The plug are new, oil level is fine, tire pressure's set at 40 for both vehicles. All things similar between the 2 cars, but a difference of 10mpg.