Hello All,

I am an owner of a 2006 F-150 STX 4.2l two wheel drive super cab pickup. I have owned the truck since 2010 with no major issues (only had to have the spark plugs and spark plug wiring replaced). Since earlier this year, my truck will ride very rough when it rains hard and it acted up today while it snowed. When it is wet out, my truck will start, idle very rough and when I proceed to drive, the truck rumbles very rough. The check engine light will flicker, stay on and then turn on and off relentlessly. While driving today, I was going between 50mph-60mph. I could have my foot pressed on the gas, but the speedometer would go down and I could feel a significant loss in engine power. The last time this happened to me two months ago, the rain had stopped and after driving for a while my truck suddenly stopped rumbling and drove like nothing had happened. What could cause this?

Dave D00m

 

I would think something is getting wet and causing problems. One way to help pin down the area is to use a spray bottle with water and spray small areas one at a time slowly and not necessary to soak them and when you notice a change in engine RPM there is most likely something in that area that is responding to moisture. Let us know if that was any help for you.

A side note, some spark plugs and less than quality wires could be responsible for symptoms like you are seeing.