If a vehicle fails the emissions test, repairs must be done to hopefully enable the vehicle to pass the test. If a citizen spends $5 on repairs and it passes, thats great.
If a 1981 or newer vehicle fails, and after extensive repairs that eventually amount to $450 in parts and/or labor from a emissions certified repair technician, OR $450 in parts alone if work is done by the owner or a non-emissions repair certified technician AND IMPROVEMENT IS MADE IN THE FAILING GASES WITHOUT CAUSING ANY OTHER GAS TO FAIL THAT IT MAY HAVE PASSED ON THE FIRST TEST then a WAIVER is granted, which allows a citizen to license the vehicle, THIS IS NOT A 'PASS' the vehicle is still failing. And if the citizen keeps it for 2 more years he/she is looking at another $450 in repairs again. So it is prudent to fix a vehicle to pass.
I have looked at approximately 2,731 failing vehicle reports/repair invoices, and a tune up has NEVER been the cure. It helps, but points, plugs, etc, has a very slight effect.
Visit the website at www.gatewaycleanair.com
for more information.