engine noise

For the last 8 months or so my car has been running on a tune that my buddy made using my sct II tuner. Today i got my brenspeed tune and before i loaded it on, i set the car back to stock and drove it around. When i drove it in stock form, at hard exceleration at around 4500 rpms, there is a pinging or sound like something is rolling around in a tin can. It still does it with the brenspeed tune. Im using 91 octane fuel, which is also what the tune is. When i go slowly up to the same rpm range, it doesnt make the sound. Any ideas? should i be concerned

Would that be possible detonation? Have you had your air/fuel ratio checked?

sounds like detonation to me also. That really makes no sense that the stock tune would do that and the custom tune wouldn't. The stock tunes are really conservative on timing and A/F ratio.

Could it be a possible dirty MAF sensor or throttle body plates?

sounds like detonation... what grade fuel and type are you using? try jumping a few octane points after a few tanks see if the problem persists

The tune is for 91 octane and thats what i was using.

What about reflashing with the 87 tune and running a few tanks of that through.

i have a question ..... when diconnecting your battery do you loose your tune or does the PCM permenently store until it is flashed again??

you do not loose the tune when disconnecting the battery.

well at least your tuner works. As soon as i install the tune my car doesn't start im pretty mad.

Check your owners manual. Sometimes pinging will occur and is normal. Everytime I changed my tune from stock to 91 or 93, it will ping when flooring the gas. However after a few weeks it went away and is fine. Dont know if the computer is adapting or what, but I would also have several other problems which would occur when ever uploading new tunes such as improper gas level, stuck rpm needle, etc. However after a week or so, the car would return to normal. This is from using tunes from SCT.