just run a few ounces of acetone and slightly unbolt your exhaust... read this
http://jason.fletcher.net/tech/sniffer/sniffer.htm
I read down to category II on that site and got pissed.
That info is for a carbed car, and may or may not work for EFI.
If you need to pass emissions, then the first thing you should do is make sure the emissions equipment is working properly.
Install fresh cats if you don't have any. $150 at Summit will get 2 high flow MAGNAFlows that will not cost you ANY hp.
Make sure the EGR is working properly.
Pull the codes to make sure there are no other problems that need to be addressed.
This should get most of our Mustangs to pass emissions.
Notice there are no 'TRICKS' being mentioned.
If you still can't pass after doing this, then you need to consider why you didn't pass.
Did you make some 'modifications' that will hurt your emissions results?
A HUGE cam?
Some things to keep in mind from the above link...
Introducing an exhaust leak before the O2 sensor in an effort to increase the 'fresh' air in the exhaust, will make your HC levels HIGHER. This is because the O2 sensor will be seeing an excessively lean condition and the computer will attempt to correct by adding more fuel.
The above link also mentioned removing the pcv in order to eliminate crankcase fumes from the exhaust. You shouldn't have crankcase gasses getting into the exhaust anyway. I don't understand that comment.
If the pcv system is working properly, it won't cause any issues.
My entire point is pretty simple.
You don't need any tricks to pass emissions.
All you need to do is get the car in good working order, and make sure the emissions systems are functioning properly.
Unless you have some wild combo, you should be able to pass.
Instead of seeing emissions testing as some bogus BS rule being imposed upon you
Look at it as an opportunity to see how well your car is actually running.
If it is running well, you should pass, at least the sniffer portion.
jason