Ok, basically I want to know if (a) I'm crazy (probably), (b) I'm not crazy but I don't need to do anything, or (c) if I should do something (ECU reset?). And if I'm not crazy, if someone that understands ECUs can explain this to me.

A few weeks ago I got a tank of gas that made the car (stock 04 WRX) run like a dog. I accelerated hard at one point, and I think it may have been pinging -- sounded like gravel in a tin can or something, and it was either me or some car around me (several cars rushing away from a toll booth).

After that, the car seemed slower. I put in half a tank of 100 octane, which helped, but still the car seems more tame than before. This is the "am I crazy/unlucky" part -- it's been warm, and I haven't driven the car a lot, so maybe I've just hit some bad days. But if I had bad gas, and it did ping, would the ECU change its settings? If so, will it eventually change them back (it hasn't pinged ever again) or does it need to be reset?

Thanks for explaining all this to someone who hasn't understood his car terribly well since they took away his carburetor.

 

eventually your ecu will continue to advance timing and will run strong again.

if you want to hasten the process, reset the ecu.

although i am not sure of this, the "shiv reset" technique, which is done after an ecu reset and increases the IAM (ignition advance multiplier) to the maximum (16, iirc) will probably work on your '04 ecu. this will immediately give you your optimal advance for max power and efficiency.

however, if you artificially increase the IAM past the point where the gasoline starts to knock, the ecu will detect the knock and pull your advance back down again. it's not magic!

hth
ken

ps quick shiv reset explained: drive off boost. then hold 2500 rpms, left foot brake while increasing throttle so that manifold pressure = 2-5psi, holding rpm steady. hold for 10 seconds.