Saturday night, as I was driving home, my car suddenly slowed down, the speed dropped to 28, it won't go pass 30. I drove it for 26 miles in that speed, took forever to get home. It does not register any malfunctions. I took it to my trusted mechanic Sunday, and until now, he can't find anything wrong with the car, its been 2 days. . Do you guys have any idea what is wrong with my car? I would really appreciate any input. Thank you!