I had a passanger side header gasket leak. Pulled everything out and replaced it with the expensive FLOWTECH looked like gaskets made from aluminium foil with many layers.

When I started the car and rev the engine a little I got pissed off again. There is still that stupid leak.(the port where the long stud screws in and the a/c bracket is attached to)

I have cleaned the headers and the head area, did everythinbg by the book, but still a little leak.

Took the car for a ride and does not seem to pull as hard as it did before.

1. Could it be the knock sensor affecting performance?

2. How do I test the sensor?

What do you guys think?

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89Iroc, 305 TPI, WC T5, 3.08 Posi, Flowtech Headers 1 1/2, Hooker Y-Pipe 2 1/2, 3 inch over the axle, Flowmaster 80, No Cat, Aluminium Driveshaft, Ported Plenum, Air Foil, MAF Screens/Fins removed, K&N, Gutted Air Boxes, AFPR @45 psi, Ram Air, Throttle Body By-pass, Bumped Timing @12, Bosch +4, MSD 8mm wires, HP Rotor, Cap and Fuel Filter, Sensi Trac rear Shocks.