6gSI

So i went to take my emissions today. Stupid me waited till the last minute, and I failed because of this code.

It passed two years ago using the same equipment that i currently have, aside from replacing the primary o2 sensor. i think the original is still good, some how one of the pins worked its way out of the plug... anyways, i just replaced it with the new one.

Here are the specs.

1999 SI
B18C OBD1 running a P28(i think? i cant remember exactly.) ecu, and a cat.
When i do the emissions, i have a P2T(OBD2) ecu that i put in, and it passed 2 years ago when i tested it.

The only thing that was different this time was that i drove the car to the testing place, then switched the ecu's the first time. This time i put the P2T in at work, then drove around for a while and went to the station.

The light came on right after they had tested my gas cap, but just before i stopped for them to plug in the obd connector... just my luck. 20 seconds later and i would have passed.

so my question:

why was the fuel system fine while driving and stuff, and then suddenly lean out like that, or lean enough to throw a code? is there anyway that i can temporarily fix it for the test?

thanks for any replys.

6gSI

bump and another question... what can i do to fix it?
will getting an USDM ITR ecu fix it?