Okay, when I put my headers on about 1.5 months ago, somehow I managed to not get one spark plug all the way in. Consiquently unburnt fuel was going through the exhasut system. At the same time I was noticing a rattle/tapping sound at around 35mph, and various other places. I am not talking about a tick like a rocker or leak, but something I could feel in the floor of the car.

Anyway, I took the car to have diagnostics run and have a compression check done. The only things wrong were the spark plug and a few small vacuum leaks around the fuel pressure regulator hosing. When I got the car back it ran amazing and the rattle had went away. Well, it is back so I don't know if maybe the fuel that was getting dumped into the system clogged the cat and that is causing it or if it is something else, but it definately seems like it is exhaust related. Any help would be greatly appreciated.

Matt

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irocet@hotmail.com

drive.to/Stang_Kilr

88 IROC-Z -- 350 L-98, 700R4, Flowmaster, Edelbrock Headers, Catco Cat, K&N, MAF Sceens Removed, Airfoil, March Pullies, Comp Cams Magnum 1.6 Roller Rockers, Bosch Platinum Plugs, Accel 8.8 mm Wires, MSD 6AL, Hypertech Cap & Coil, Hypertech Chip, Hotchkis Strut Tower Brace

 

Sometimes the insides of a cat will break into pieces. Sometimes a piece may spin from exhaust flow. Sometimes that piece will stick and not rattle, then get free and rattle again. I've had this happen to me.

 

That is kinda what I was thinking. I am going to have a straight pipe made tomorrow and see what that does. If it quits rattling, I guess I'll know. Thanks for the help.

Matt

------------------
irocet@hotmail.com

drive.to/Stang_Kilr

88 IROC-Z -- 350 L-98, 700R4, Flowmaster, Edelbrock Headers, Catco Cat, K&N, MAF Sceens Removed, Airfoil, March Pullies, Comp Cams Magnum 1.6 Roller Rockers, Bosch Platinum Plugs, Accel 8.8 mm Wires, MSD 6AL, Hypertech Cap & Coil, Hypertech Chip, Hotchkis Strut Tower Brace