Don't use high octane gas. The engine is made to run regular 87 octane. You also just adjusted the ignition timing for regular gas.

Have you recently jumped the CEL connector to look for codes?

How is the engine idling?

One possibility is a lazy O2 sensor. In addition, the noisy valves could indicate that you need to adjust the valve clearance. If it is out of spec, you could get low gas mileage.

 

it's not like it can hurt...

i still stand by saying that lucas oil stabilizer and lucas fuel additive work wonders!

 

No RONJ is right don't use any octane higher than what the manual says. You should only use premium in the SI models because the owner's manual requires you to. I have done research on the expensive fuel is better concept and it's not. I think i had read somewhere that higher octane actually is hurting your car by giving it more octane than what your owner's manual says but i could be wrong about this. My manual says 86 octane but the lowest here is 87 which won't make a difference but pouring 92 into 86 is bad. Stick to what your owner's manual says as the owner's manual is telling you right information.


Look here for more info:

http://www.ftc.gov/bcp/edu/pubs/cons...tos/aut12.shtm

 

I wasn't saying it was BETTER. I was saying it has more fuel additives in it that do more to clean your engine. I'm suggesting he runs some through it once because of the additives, or use some Lucas Fuel Additive (or whatever it's called).

I'm tuned to run 91+ octane anyway, so whatever.

And i'd like to see some proof that it's bad for your engine... it's not, it's just a waste of money to use it on a regular basis unless you need to.

 

while many are loud at idle and cold, it is because a honda motor needs to regularly have the valve clearances adjusted. Chances are that it probably hasnt been done in quite some time. I dont remember the recommended time frame when it should be done, but I do it every 3k miles or so

 

I believe the maintenance schedule says every 15k miles. (just throwing that out there)

 

I need to read more on this topic, but this site says that higher octane gas does not contain more engine-cleaning fuel additives. It also says that the use of higher than recommended octane fuel results in higher emissions and can harm the catalytic converter.

 

Depends who you buy your gas from.

makes sense... unburned fuel as a result from less resistance to burn.

maybe that's why i'm running rich... i really need to find a gas station with 91 octane (all ours are 87, 89, 93) or start mixing 93 and 89

 

Regarding RonJ's question about my idle, it still idles sucky occasionally. For instance, on two occasions today, during different driving sessions, my car appears to idle around 500rpm. When I put it in neutral, the idle drops even lower, to like 400rpm. It shudders during this. My exhaust kinda smells a little gassier than I'd expect too... I will check CEL again tomorrow. I have rechecked timing and CEL a few days after adjusting the timing with no problem, but I'll glance at it again...

 

Is the engine idle low only when the engine is warm?

A rich running engine (low gas mileage) + low idle = clean the IACV and check/replace the PCV valve.