Help me diagnose a problem please, my car has been idling kind of rough and seems like its lost some power. I recently switched to 91 octane for a couple of tanks and it helped, it idles a little smoother and seems to have more power and run smoother in general, then switched back to 87 and it seems to run like crap again. My car also idles a little fast, around 800 rpms or so, but in my helms it says check ignition timing, clean throttle body, etc. first. EDIT: gas mileage w/ 91 octane was better (25 mpg city) than w/ 87 (around 20-22 mpg).

Could the ignition timing be causing this or should I look elsewhere first? I've recently changes plugs, acl, and had a valve adjustment. I'm about to change the plug wires. Thanks


[Modified by p0pe, 6:15 PM 12/26/2002]

 

What car are we reffering to? What year and how many miles?
You changed plugs and soon wires, what about a new dist cap? How about a new fuel filter? Age + injectors + fuel filter + bad dist spark = rough idle and bad gas mileage.

 

is there a swap involve or just the oem engine and what car is it

 

sorry, its for my 97 accord ex, 72k miles on it, no swap.


[Modified by p0pe, 7:32 AM 12/27/2002]

 

Do the wires and then adjust your base idle, and then your timing advance. You should good to go after that.

 

If it's idling a little fast, and runs better on higher octane, sounds like the timing is too far advanced.