96 3.0 with code P0430

My 96 windstar seams to get a new code every time I travel to Florida. I go all year with no problems, then in Dec. traveling from Indiana to central FL I'll get a engine code after the first fill up. Once in Fl the engine light goes off and mileage comes back to normal. Then on the trip back just after the first fill up, the engine light comes on. Once back In IN after a few fill ups the light goes off. This winter code P1131 came on, I had it checked as soon as I got to FL. Then light went off while there in Fl and back on, on the trip home. This time the light has not gone off and the code has changed to P0430. My gas mileage has been poor, about 16mpg. I'm usually around 19-21 in town. Pickup seems poor, just like all the get up and go got up and left. This is my service truck is loaded fairly heavy at all times. I am going on a 1200 mile trip soon and at the present gas prices would like the van to get reasonable mileage. I had a fouled plug in cyclinder #3 this winter. Used Bosch in stead of Motorcract. Could this had plugged cat? Any suggestions?

Take out the oxygen sensors and see if they are clogged up. If one looks bad try replacing it.

Whitch O2? Code 430 is on bank 2 (Catalyst efficiency below threshold), code 1131 is (lack of HO2S switch-sensor indicates lean). What side of engine is considered bank 2? Now in the last couple of days the engine idles very fast at start up, then slows down to normal after a few seconds. Any additional thoughts??

Hi
On the 3.8L, bank 2 is across the front with cylinders 4,5,6. I would think it likely the same on the 3.0. The oxygen sensor that MAY be causing the problem would then be downstream of the catalytic converter for that bank. From what I have read, the oxygen sensor in that position looks for a certain exhaust condition for a limited amount of time (I know, vague) on start and warm up, and then pops the code if it does not see it. i.e. the downstream sensors can be the actual problem with a 430 code. I would not bother to pull them just to look at them. Other than some green discoloration seen on the upstream sensors due to gasket leakage, I have never read of a visual inspection yielding any information. My failed sensors have always "looked" fine. For what it is worth, my friend's Taurus was throwing the P430 code. We ordered a new O2 sensor, but the code went away first and has only returned occasionally. So, watchful waiting may be in order, unless you truly suspect a clogged system.

Good luck

When you pull them out, you look for the obvious. If one is clogged up with carbon, that would be an obvious sign of a problem. Try replacing it, see what happens.