94 Conversion B250- Motor Hesitates and has very little power after river crossing

[mendo]

Ive got a 94 B250 Conversion Van with a FI 318.
It ran great when I first got it then I went through a river crossing that was probably up to the bottom of the bumper and when I came back out on the road it had barely enough power to move. I kept driving it and the power got better but it has not been the same since. When I floor it, it hesitates for a sec and then starts going but is extremely gutless. Once I am up to highway speeds it does fine and will cruise 90mph no problem. But off the line its just rediculously slow. Any ideas on what happened to it? Water in the tranny or clogged exaust or cat im thinking. Thanks

[alloro]

Your oxygen sensor probably got submerged. When this happens, the O2 sensor being hot is immediately cooled. This causes the crystals inside to fragment and usually end up causing the fuel/air mixture to lean out, resulting in a loss of power.

[mendo]

Ah interesting thanks. Wouldent that cause the check engine light to come on though? How do I check to see if its damaged?

[B-300]

Some 02 sensors also has a very small vent to compare atmospheric 02 to exhaust 02. If the 02 sensor is slow to react it won't throw a code, unless it stops almost completely.

[alloro]

How do I check to see if its damaged?

http://www.gnttype.org/techarea/ecmsensors/O2sensors.html