Question about resetting PCM and gas octane

[soctty7676]

I have always run 87 octane in my '98 GT with no problems at all. The other day I drove up to Wal-Mart for a new battery, switched them out in the parking lot and drove home. Apparently, just unhooking it for 1 minute reset the PCM because when driving home, I stomped it hard in first and second, and the car was pinging BAD. The next day after driving to work and back, I romped on it again in first and second with no pinging at all.

So I am assuming the pinging was from the PCM trying to dial in the timing? If so, wouldn't the car have more power if I switched to 93 and reset the PCM? This way it wouldn't have to pull the timing as much. I've always thought you wouldn't gain any power by running a higher than recommended octane, but this makes me wonder?

If this is stupid, just tell me, and I'll put the crackpipe down.

 

[DBMSTNG]

no, the GT has no way of knowing what octane you are running. the pinging could have been just a little bad gas, or something else.

 

[jstreet0204]

The computer does not adjust timing based on anything in the memory that was cleared. It could have been a little lean until the fuel trims were reset that caused the pinging, and no, it will not adjust to the octane you are running.

 

[soctty7676]

Ah, that makes sense. It's probably adjusting air/fuel, not timing.

Ok, nevermind....

 

[Mike97gt]

what happend is when you pulled the battery cables off you reset the KAM ( keep alive memory) when you do this you return to the base fuel map since the PCM lost all of it's learned adaptive strategy.. it takes a little while to relearn that so you were a little lean untill it fattened the mixture back up..

this is normal as the car ages for the stock base map to be a little off.

and to answer your question, NO you will gain nothing by going to 93 unless you get a tune for it.