Rattling Problem

Hi, I'm a newbie here but not new to the mustang forums scene....anyways

I wonder if you might give me some insight to this problem I've been having with my stang....I've been running an SCT performance tune on my stock 04 gt for about a couple weeks to give it more pep and change the shift points for my auto trans. Then one day I heard this "rattling type noise" (not sure how else to describe it) which occurred occasionally whenever I stepped on the gas. Scared it might be detonation I quickly returned the car back to stock form. For whatever reason or another I continued to run premium fuel even when I was with a stock tune and I dont hear the rattling as much but it is still there and noticeable. So I'm not sure if it was detonation in the first place but I know the rattling noise is louder and more frequent when I have the tune in. Stockwise it happens less frequent and is not as loud. I'm not sure if something is loose or what. I already tried the local Ford service place since I'm under warranty and "complained of a rattle". Course I drove the the required miles after returning it to stock to wipe the car's memory of ever being flashed. The said they drove it and found nothing. But at least its documented at the Ford service place. So anyways sorry for the long drawn out explanation but if you guys got any ideas what it might be or any place to go to that might be able to help me, give a shout. Thanks guys
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sgarlic said:

Where does the rattling noise sound like it's coming from? Engine side, rear end, below you, interior, etc?

Secondly, have you made any other mods to it lately that you can check on? I.e. just swapped midpipes or catback and didn't tighten everything?

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It's coming from the engine compartment. The only thing I did was install a K&N Filter and I checked to make sure everything was correct with that.

twogts4us said:

ANd you indicate that though the problem didn't completely go away when you returned to the stock tune, it did diminish the 'pinging' or whatever you may be hearing - is that correct?
If so, boy, that sounds like pinging (detonation) to me. Maybe you got some crappy gas? Is this 91 or 93?

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Yeah thats correct it did diminish the pinging. I've been running premium for a while even stockwise. It's octane 93 and I've tried it from a couple different gas stations in the area in case it was bad gas. I'm wondering if maybe it has to do with the timing chain possibly? I was running stock this weekend and driving on I-95 doing 75mph and I was hearing it. This is really buggin the hell out of me. On and off I keep thinking its detonation but I'm wondering why I keep hearing it running a stock tune and on premium fuel. Think maybe I damaged something?

twogts4us said:

Take it back to Ford and take the tech (or service writer) for a ride...duplicate the problem for him. I'm not so sure this is pinging...not likely at cruising speed. I thought I read of a TSB for premature wear on the chain guides...or am I dreaming? LOL Either way, I'd take er back to Ford. Keep us posted and WELCOME to StangNet!!!

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Thanks man, whats TSB by the way? Anyway the problem with bringing it to Ford is that maybe I'll hear it once a week and thats it stockwise. I figure if I bring it back I'm gonna get the same answer saying no problem found. I'll probably mention it to them next time I get an oil change from them again to at least have them have it documented a second time.