Car engine sounds like it's filled with water when it rains?

I have a 1999 Toyota Corolla automatic that has for the most part been a fairly reliable vehicle, minus a few minor up keep and wear and tear type things that need to be worked on but the car engine generally sounds fine and drives perfectly despite having over 120,000 miles except for sometime when it rains heavily (which happens fairly often in Oregon during the winter) there will be a lot of water on the roads and a lot of rain coming down, and it is in this type of driving condition that I have been experiences what seems to be either an engine or transmission problem. What happens is when I head out on the town under these weather conditions and try to accelerate and get into passing gear the car gets stuck, almost like when your having trouble getting the car into the right gear and the rpm’s rev up high and it makes this muffled gurgly noise like the engine’s about the fail or like someone dropped the engine in a giant pool of water and it won’t accelerate anymore and stays in a lower gear and won’t go into passing gear. I think the fastest I’ve been able to get it to go at this point with my foot all the way down on the gas is about 45-50 mph. To resolve the problem I have to let my foot off the gas and then gradually introduce more gas into the pedal in a slow pumping motion until the proper acceleration or passing gear returns, but sometimes I never get back up to speed and continue to have the problem through the day until the weather clears up. Once the weather improves, it stops a raining and the roads are dry the engine and transmission are magically back to normal. I told a mechanic about it but they of course tested it right away on the road when it wasn’t raining and told me they couldn’t reproduce the problem. They also put it on one of those machines where they accelerate the engine at different rpms and see if they notice any problems on their diagnosis machine, but this didn’t turn up any problems either. I’m really out of ideas here and just wish I knew what was causing the problem because I feel like it’s probably something easy to fix. Can anyone help? Thanks!

This may or may not apply in your case…check for missing shields near the exhaust oxygen sensor. I had an older Malibu with computer controlled carburetor, that did just what your car is doing. When water splashed up on the exhaust pipe where the O2 sensor was located, it caused the carb to go real lean and the car would slow down to about 45mph. In my case the car was missing a metal shield that should have kept cold water off the pipe and sensor. Caused it to read erroneously and lean out the mixture. HTH.

Thank you very much for the advice. I’ll double check this and let you know what I find out. :slight_smile: