I will do that, at least as a start...

I've seen all sorts of crazy stuff concerning the Secondary Air system:

1) pump being bad
2) fuse in ECM compartment blown
3) combi valve failed
4) adapter attaching it to the head being gummed up and not allowing air to flow into the head.
5) vac leak to combi valve
6) relay bad
7) solenoid that sends vacuum to combi valve bad
9) line between airbox and pump having pinholes

I did some thinking and realized that maybe the P1128 long term fuel trim too lean code I had due to the bad MAF actually may have been masking this underlying problem.

Basically the point of these EGR, and SAP systems is to pump air into the head to artificially lean out the mixture during a cold start, hence raising EGT's and subsequently warming up the catalytic converters quicker so they reach their operating efficiency.

Now, this whole system only engaged upon a cold start, and runs for a grand total of 100 seconds. Apparently it helps emissions, as my 1.8t is considered a ULEV for the year 2000. Forgoing the discussion on the necessity of the system and it's effect on emissions, it is required and has to be operating properly here in NJ to pass state inspection. All they basically do is plug in and check for no codes, and all readiness monitors ready.

BUT what I started to realize is that the car has no ECU connection to the SAP system to check flow. All the ecu does is tell the SAP system to engage based on some measure of engine temperature. This inadequate flow detected code simply must be a guess by the ecu based on not seeing the leaning out condition it's trying to create based on the pre / post cat 02 sensors.

Since the car had a bad maf when I got it, which manifested itself as a p1128 long term fuel trim too lean code, but the fuel trim was not that bad at idle. So maybe the maf was covering up this SAP fault?

Ok I'll get off my soapbox now...

George