I have a 96 Mazda Protege DX. 1.5L engine, now with 161,000 miles. 5 speed manual transmission. I had it for 7 years. Originally bought it for $1900 with 121,000 miles.
This has been a problem for about 5 years. When I am at a red light or idling and I step on the brake, my idle gets rough and my engine feels like it is about to turn off. The idle does not bounce up and down. It just goes down to 400-500rpm from the normal 800-950rpm range.
Again, this only happens when I step on the brake while the car is not moving. It does not seem to happen when I coast in neutral and hit the brake to slow down. I raised the idle a bit, but it still does it. I could not find any vacuum leak around the brake booster and I know the brake booster works because I pumped my brakes while the car was off, and when I turn the car on, the brakes soften up.
Also, my brakes feel weak. I usually hit the brakes nearly to the floor board to stop the car. New pads, rotors are good. Brake fluid is at right level. Mechanics say nothing is wrong with my brakes.
Secondly, my belts screech at every start up. Lasts anywhere from 3-20 seconds. This has been happening for the entire 7 years I have owned the car. Mechanics replaced the serpentine belts twice in that time. Replaced a pulley and A/C compressor. I tried using WD40 but it doesn’t effect it. Mechanics tell me that the belt tension is correct and they do not know why it still screeches.