My 1990 V8 sputters, loses power and dies if it hits a puddle. Doesn't have to be more than an inch or two, and 25mph will do. Once the car dies, it starts right back up after turning off the engine and restarting. This has gotten much worse since the underbody shield came off. I have recently replaced the ignition wires but this didn't help (but the replacement was way overdue anyway).

Can someone help please with a suggestion as to what is getting wet?

(By the way, the shield came off at 75mph, presumably because my garage didn't properly affix it the last time it was in. Yes, that's the same garage you may have read about in my last post. No, they are no longer working on my car. No, the new guys are not much better. Suggestions for competent Audi mechanics in metro Detroit are much welcome!)