My 99 GSR is failing Colorado emissions, here are the details.

Car is tuned on a VAFC - relatively stock car, ITR catback, DC header, ITR pistons, LS crank

Everything else is stock. Here are the results with the first go-round:

HC Readings : Allowed : 1.2 - Emitted: 1.7
CO Readings : Allowed : 15 - Emitted: 34

After this reading, the oil was changed, seafoam was run through the car, changed the plugs (after the seafoam) and car was run hard on the way to re-test (next day) to warm up the cats

Here are the readings this time:

HC Readings : Allowed : 1.2 - Emitted : 3.4
CO Readings: Allowed : 15 - Emitted : 55

Is it possible that when the seafoam was run through the car, the O2 sensor was fouled causing higher readings?

Any help is much appreciated!

 

Anybody have any ideas on what to do?

 

How far is the drive to the test place? If it's 30 minutes or less try driving at least an hour before the test. Also if you go on a cool day your numbers should be slightly better.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Ninjak &raquo;</TD></TR><TR><TD CLASS="quote">How far is the drive to the test place? If it's 30 minutes or less try driving at least an hour before the test. Also if you go on a cool day your numbers should be slightly better.</TD></TR></TABLE>

Thanks.

Any other thoughts?