EX Running Rich

[dvd5904]

This past weekend I replaced the knock sensor in my 96 EX. To do so I had to remove the IM. I replaced the gasket and all hoses seemed to fit back correctly and in good shape. I also replaced the O ring behind the distributor. Afterward the car accelerated poorly, sort of stumbling through the low RPM of each gear. This is where I learned about Ignition timing! Lol. I bought a digital timing light and found that the I-timing was way off. I got the timing back on track and the car runs better than it ever has. The problem I'm having is that it is running rich. I can smell fuel in the exhaust. The CEL came on and is code P0138 (high voltage O2 sensor #2). That would again verify a rich exhaust. I'm getting the usual punch list of areas to look at together and thought I'd see if anyone has any ideas?

[dvd5904]

When I post, I try to keep a complete thread going. Most of the threads on this forum start out detailing the issues, followed by some suggestions, but then have no conclusion. Not very helpful to others who are trying to solve the same issue. So for that reason here is where I am with this:

Potential Causes for Running Rich
1. Evap Canister Filter Clogged or Saturated (Long shot)
2. Fuel Injector Sticking (Unlikely)
3. TPS not positioned right (Not sure that can even happen)
4. High fuel pressure (Doubt on stock ECU, fuel rail, and injectors)

It's a hurricane outside, so I'm still thinking this thing out before I get under the hood. I suppose the ignition timing could still be off, even thought the timing light showed the mark lining up perfectly. A prerequisite for setting I timing is having the engine at OT and the idle at spec. My EX has always idled around 1K, which is high. This may have caused the I timing to set wrong even with the timing mark lined up? Off to more research....