2004 Buick LeSabre sputters in wet weather only when accelerating

Question

My 2004 Buick LeSabre recently started behaving strangely. At first I thought I had filled up with some "bad gas." I used Heat to treat and after a week or so it seemingly started to work fine.

Then today, it is raining pretty steadily and as I was driving on the interstate, it started sputtering again. This was after about 10 minutes driving in the rain. I can set the cruise control and it will run "fine" until it needs to accelerate. Same thing happens when I come to a stop and need to accelerate to get up to speed. I have to slowly accelerate, giving it only a intermittent tap on the gas pedal until I get up to speed, otherwise it nearly dies.

Any idea on what this could be? I don't want to take it to the dealer for exploratory surgery until I have a somewhat educated idea of what the problem could be.

Answer 1

First guess, bad spark plug wires. You can check by first, doing a visual inspection of the wires, looking for burn spots, particularly if the wire was touching/rubbing on something. Second, on a dry night, crank the engine and lightly mist the wires with a spray bottle of water. You will be looking for a spark to ground and you may also hear it.

Beyond that, it could be the coil shorting out, bad ignition module, and the list goes on. Information about the check engine light status, codes stored, etc. would also help with the diagnosis.