this is what I know about my wifes 97 Civic LX...very little! It's stock w/180k miles on it. (I was told...) the VSS and both O2 sensors (are there 3?)were replaced about 2 yrs ago, along with the alternator. (I (again)replaced) the alternator 1 yr ago. Also I replaced the VSS sensor yesterday.
I had AutoZone check the OBD2 codes today and this is what they told me.... VSS voltage out of range, IDM failure (what's a IDM?), OS1 and OS2 bank 1 fail, PO420 - catalyst or vaccum problem, 302 & 304 - misfire, 1305 - EGR problem.
Here's what it's doing:
1) shifting erratically and spedo "bouncing wildly"; it just started doing this and i replaced the VSS....yet it still does this and still shows the VSS code.
(I checked/wiggled hoses and wires around under the hood and it was OK for awhile-then acted up again, leaving me to wonder if this is a vaccum or electrical problem)
2) dash lights (dome, etc) "surge and fade" like it did last year before i replaced the alternator....just started this again (and I wonder if its something else besides the alt)
Since I've known her(wife and car both):
3) CEL always on
4) Tach registers wildly (told this was a Engine Speed Sensor that was very expensive and wasn't replaced cause it didn't affect anything else)
5) SRS light on (due to a fenderbender I think it was never reset)

**Please help me - she gave me 7 days till she buys a KIA(gulp).....then I'll be using windows 98 on this old PC another 5 years!!!