Shimmy/Shiver/Vibration

[Guest]

I have had this problem it seems since I got my headers. When I start the car and its cold, sometimes when its warm, I get a shiver through what feels like the rear end area right when it fires up. Ive been tracking it down for almost a year. Its not a heatshield in the rear. Today I think I discovered its not actually the rear, but the front, around the header y-pipe area. It doesnt really occur when turning rpms, but it occurs when the cars rpms drop, like if I blip the throttle in neutral, on the way back down it shivers. Its very annoying and gets pretty loud, and its embarrasing when I fire the car up and a loud grrrvrrrrerrrerratttlerattletat :D
Anyone have any ideas? Thanks
John

[matt3989]

did you check the flange on the Y-pipe? you might wanna try tightening it

ive also heard of people having s
omething in their cat, but i think it would happen more often if it was something like that

[Guest]

The cat is a new highflow. I used new bolts on the flanges due to the pacesetter problem with wrond sized bolt. I replaced them not to long ago. Thanks for reply,
John

[BLLDOGG]

i still wouldnt hurt to check them. i never had this problem with mine so im just going to throw out some thoughts. is the y-pipe touching the tranny? that would cause a vibe

[Guest]

I just checked the bolts are all tight, its clearing(just barely) a tab on the engine/tranny. The shop that welded the exahsut up made it very tight I mean you cant shake from the back. I think its got way too much tension in it. If I hold a screw driver to the pipe it bangs away, lots of harsh pipe movement, so im sure its exhaust doing it, I just cant pinpoint where. Thanks for reply.
John

[BLLDOGG]

if its close enough, the potential movement of the tranny might close that gap. try maybe looking for rub marks or marking all over where you think it mighe be rubbing to find a fresh mark.