2003 Toyota Matrix engine problems

I took the matrix in twice shortly after I bought it because the car would unexpectedly lunge forward while at a complete stop. I also complained that the brakes felt "loose" and did not "catch" as they should. I was advised both times by the service manager that they could not duplicate the problem and that nothing abnormal was found with car. While I was beginning to look into "lemon laws", in september of last year I was at a stop light with the brake pedal fully engaged.

My son was driving our 2003 toyota matix, accelerating up to speed after pulling onto the interstate on-ramp when the engine began to make a loud clicking sound. There was no engine warning light or smoking from the engine or exhaust system. He reduced speed, pulled over and exited at the next exit. Although the car had lost significant power, he was able to continue to drive to the dealership, located nearby. The oil pressure switch had failed and the oil had leaked out. There was no level on the dipstick.