I know what the 31 and 21 is but two 42s in a row? What does that mean? O yeah, I still can't find where the leak is at. I thought at first it was just one of the small rubber hoses that was connected to the tb. Replaced it but still produces that 31 after being reset. And the code 21 comes and goes. Sometimes its there, sometimes its not. So do I really need a new o2 sensor or what? Thanks for the input.

I have the same sort of thing going on. FOr several years now. :sigh

I have replaced several vac lines to no avail. One time it was suggested that maybe the rollover valve on the gas tank was to blame. :shrug

CEL31 is my co-pilot. If it's not lit, then I get nervous. :P

same here as ^^^^, have a code 31 on my current eclipse (97) and had it on my previous eclipse (98).

That sux! Awwwww man, don't tell me I have to go to those "places" to have my car smogged just cuz my cel is on for a stupid code 31... x( Any idea about the 2 code 42's tho?

MFI (Multiport Fuel Injection) relay (ASD relay) control circuit.
Harness and connector / Fuel pump relay

I have no idea either.

Anyone else? All I know is that the CELs came on after doing a compression test.

Did u forget to put back the relays?

uhm are the realys making good contact? I know that mine have some dirty looking grim on them. Double check everything. If it came one after the Compression test and the codes point to a relay ( the pump and ignition ones you disconnected come to mind)then the problem is most likely around that area.

I'll check. But if the relays aren't connected right, shouldn't the car not start?

if the relays are bad or on the way out it could throw the code if it relates to it directly.
Michael
99gs HRC Stage IV 8-Injector Setup
2GNT Member #32