I don't drive my car much, and pretty much never in the summer, EXCEPT when it needs inspection. This year, I took my car out to put a few miles on it and get fresh gas prior to an oil change and my annual new brake rotors (rusted). The car was runnin great, until it wasn't.
The engine refused to go above 2,600 RPM. Even in neutral and the throttle floored, nothing. Fortunately I was up hill from my mechanic, so I limped down and through town, going slightly more than walking pace for some of it.
It turns out it was mice. They are a royal pain for me. They ate throught the air filter, and stuffed all kinds of debris in the intake. Some of this finally blocked the throttle plate (electronic) so that it would not open up enough. Caused all kinds of fault codes. There was also plenty of junk in the cabin filter, which was blocking their entrance to the heater fan. Fortunately they did not get into that as that can get very smelly after one goes for a spin in the heater fan.
Basically, they were treating my engine like their very own Habitrail.
SO....... I needed a way to keep the mice out of the engine. I cut up a screen that was laying around. This screen was originally made to cook fish on the grill. Keeping mice out of the engine seemed like a better idea. It fit great, unfortunately it was on the engine side of the filter. There was no reasonable way to put on on the other side. This meant that the mice could still eat the filter and cause havoc, they just could not get into the engine.
They had already gotten into the air box and put acorns in there. This was surprising since the car was parked as far away from the chipmunk wall as possible. Something had to be done.
I took a large pill bottle and loaded it with moth balls and put some holes in the cover. This is stuffed into the hole where the air comes into the air box. The only problem is that it has to be removed prior to driving the car. This is fairly quick, and once winter starts I should be able to leave it out. The screen will keep them out of the engine, but this will ensure they do not cause any damage over the long periods the car is stationary.