Fuel grade

[Mudrunner]

iirc I had that same code on a Dodge Dakota and it was there for 2 years till I finally changed spark plugs. Light went off and it was fantastic.

 

[GFO]

I'm about to get a smog check in a week or so; I know my cat is on the edge of dying as last check it barely passed. How much of a difference does premium make?

I normally run 89, sometimes I do 87.

Thanks for the info, will definitely fill up with premium then beforehand

 

[cnutco]

My '03 has the suggestion of running premium. I am currently running mid-grade with no issues.

I have also had some issues in the near past with O2 sensors. I found that anything less of the Denso sensor tends to fail... New or not.

 

[SoCalMonty]

I got the codes (P0171 and P0172)

Keep in mind, I've already changed all four O2 sensors (with Denso's not Bosch), cleaned the MAF, checked the injectors (not clogged and working). Right now I can only figure it might be a dirty fuel filter....

PS. The Check Engine light keeps coming on and off. One day it's on, one its off...

Could be fuel pressure regulator or coolant temp sensor. If you have the means, I'd do a fuel pressure check.

Ignition system is also a small possibility, but it's probably in the fuel system.

Good luck!

 

[rajin cajun]

Gen 2 91

The owners manual specifically addresses the DOHC with a minimum of 91 or 95 RON

Super unleaded has always given me the the best MPG. I can only get 91 here, but in other parts of the Country 93 is awesome and awesome at sea level.......

 

[Clem]

I don't know if it is true or not but Wikipedia says RON (Research Octane Number) is not the same as PON - Number on the pump (Pump Octane Number) or AKI (Anti-Knock Index).

http://en.wikipedia.org/wiki/Octane_rating

YMMV,

Clem

 

[off-roader]

The owners manual specifically addresses the DOHC with a minimum of 91 or 95 RON

Super unleaded has always given me the the best MPG. I can only get 91 here, but in other parts of the Country 93 is awesome and awesome at sea level.......

It also says if 91 is not available 87 octane is useable. FWIW, using my technically advanced & highly calibrated butt-o-meter :ylsmoke: I have noticed neither a performance gain nor a mpg improvement between the 87 or 91 octane.

 

[RERM]

I will admit, I get slightly better MPG's on Premium, the light is back off btw....thanks for the fuel system check idea, I'm gonna do that and a filter change ASAP.

 

[off-roader]

I can only get 91 here, but in other parts of the Country 93 is awesome and awesome at sea level.......

I used to think that about Ca. gas stations but after owning my Audi B5 S4 (essentially an A4 with a twin turbo v6 engine instead of the I4 turbo engine) I quickly learned there are a few independent stations that do carry higher octane gas (at a real premium too). I also learned that you can buy it at the local race tracks (Mazda Laguna Seca and Infinion Raceway) for $$$ (2-3x/gallon).