After Auto-RX and FP60, Mileage keeps going down

[Screwdriver]

If anyone would care to search for my previous topic, I stated that my mileage has dropped from 30 mpgs to 26-27mpgs after using ARX.

I've since used 1/2 gallon of FP60 at recommended doses and my mileage has since dropped to 24-25mpgs (measured accurately today)

Details:

1) 1998 Hyundai Tiburon with 115K miles on the Odo.

2) Full Clean/Rinse cycles performed at
recommended intervals with dino oil.

3) Currently using Mobil 1 EP 5W30 with MB1 EP Filter + ARX Maintainence Dose. Oil has 5K Miles.

4) The Cat Converter has been partially clogged since I've owned the car. Nothing new.

5) The left wheel bearing is squeeling and needs changing

6) Car feels better after the ARX treatment. Just seem to be getting less and less gas mileage.

If this were December, I'd blame the winter blend of gas. But Illinois has likely switched back to warmer temperature gasoline blends.

I'm left with few explainations. Please help.

 

[mechtech]

We ARE still using winter gas around here [Chicago area].
I'm sure your bad wheel bearing is not helping, and the plugged cat isn't getting better, only worse.
These things could for sure cause a drop in economy.

 

[Screwdriver]

Are you certain about the gas?

In the last week or so, I've felt a noticable difference in the feel of the car. It's not just my butt dyno. The car drives alot peppier. Usually happens when the blends change.

 

[Steelhead]

a partially plugged cat will just continue building up exhaust restriction flow as the plugging/contamination continues
destroys the O2 sensor which sends the fuel mileage down drastically
you'll be in the teens shortly
check with your state DOE for winter/summer gas switch, most states don't switch until mid April

gas companies are dumping in more ethanol year around, law allows up to 10% year around, cheaper than real gas with Federal tax subsidies

 

[reyjay1]

There are some Ills that will not be cured by chemicals alone. with decrasing gas milage first thing to do is change spark plugs, plug wires, distributor cap and rotor, maybe will even need new coil as original one can be degraded by time and weakened by running with the above components in poor condition, if it has an ignitor that is another component in the chain to go bad, occurs less frequently. With good electrical system time to move on to manually cleaning ERG valve and pipes, and if equipped Idle Air Control, and possibly entire throttle body. There are many clues in the way the engine is operating as to which will need doing first.

 

[reyjay1]

PS. Clogged cat converter continues to increasingly clog until gas milage goes to zero.

 

[AcuraTech]

You answered your own question. The cat is plugged and the wheel bearing is bad. Eventually the cat will become so plugged that the car will not start. Replace both these items and then see what your gas mileage is. It is definetely not the fault of ARX or FP.

 

[T-Keith]

With those known problems I'm not sure why you're looking for more.