title says it all. After I got done installing my header and testpipe i hear a rattling noise whenever i accelerate but it only last for 1-2 minutes then it's gone but starts up again if i turn off my engine and start it up again. Anyone know whats goign on?

 

Check all your heat shields?

 

+1 on heat shields, make sure that your piping isn't hitting off your sway bar (if you have one).

 

id spray the pipe bots iwth some lube and try tightening them again... they might have not been tight or something between the flanges or even a crapy gasket not fiting tight....
or start it up and then try tightening the bolts again while the pipes start to heat up... just try not to burn yourself on the pipe!!!!!

 

okay the heatshield is not the problem and all the bolts are in place correctly and tighten with the right gaskets. But what i dont understand is.. why does it only last for 1-3 minutes then go away? if it was a bolt then ir would've stayed throughout the whole ride but it only last 1-3 minutes then goes away.

 

with different temps metal shrink and expands.... which would give it some movement...

 

i had a similar problem it turned out that the bolt that goes through the floor board to hold my seat belt next to the seat was hitting my exhuast pipe