Need some help. I purchased a 1993 accord auto with 185,000 miles. It throws code 43 about 5 minutes after starting and driving the car. It runs and drives perfectly fine with out any power loss. It gets 350-360 to a tank. I found a intake manifold gasket leak by spraying brake part cleaner around the IM and then when I sprayed around the IM flange. It started to idle down and almost does. Any help would be greatly appreciated.
Thanks

 

It could I suppose. Normally this is the oxygen sensor starting to go out.

It can also be a stuck injector or low fuel pressure.

I would fix the leak and get a new Denso oxygen sensor. Don't get Bosch as they suck for Hondas.

 

I changed the spark plugs the other day and they all look the same brown ish tan color so I highly doubt that its the injectors but who knows. I went over and tightened the IM bolts up and the leak whent away but the code is still there. I will be changing the fuel pump this weekend. Ill look into am the oxygen sensor.
Thanks