cueballsi

Well everyone i am trying to pass smog and all i have are bolt ons...... my HC ppm are like stupid high at idle??? what can it be ???? it will pass at the 2500 RPM test. No CEL and the timing is dead on at 16. co% is really low ... like 15 so yea is it the cat u think???

degooser

put your stock exhaust manifold back on aftermarket headers are known to take the heat used to heat up your cat up away...thus, bringing down their efficiency (cats)

should be done before your test if not already...
-plugs
-cap and rotor
-oil and filter.. now i have used one step thicker oil and gotten better results..but new oil is better than old
-o2 sensor
-drive around at least 20 mins before your test and let the car idle while you are waiting
-check ur timing
-pcv valve if your car has one
-lower octane promotes a cleaner burn (higher octane takes longer to burn) HC's are produced by unburnt fuel and
-iso heet in the red bottle (b cruz's seceret to passing smog )
-might as well put ur stock intake on too..also you can test your car without the filter clogged filter i believe also adds to high HC's..

im sure i missed something...

good luck!