Water shorting out firing/sensors
I had the problem with my 02 when I power-washed the engine. I pulled off and dried out the connectors on the right side, & it ran fine A month later I was driving across a 'low water crossing' ( 4 inches) at 30 mph. As soon as I started excellerating, it would back fire. The check ehgine light would flash on & off as I stepped on the gas. I went home, pulled out a hair drier, pulled all the wiring off 1 at a time, and applied dielectric grease.
The next day, I went back, crossed several time at greater speeds to see if it would happen again. I could not get it to short out.
My 2 cents: