2003 chevy impala impala shakes when brakes applied

sounds like tie rod or ball joint, go to front end place, speedy or muffler man someone that does front end work

Have your tires checked out it sounds like there at around. Or possibly you through a counterweight off. Only other thing that I can think of would be the rotors being bad. However the shaking would only happen when you apply the brakes and you could feel it in your steering wheel.

run the fault codes and look for problem cam or crank position sensor
could be a problem engine mount that is being started by a misfire

Rotors are bad or ball joints are bad

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check the tires for knots or lumps, remove tire and wheel check brake pad and brake rotor. sounds like its either a brake problem or a tire problem.

more than likely you need to have your brake rotors resurfaced or replaced

not much to go on here, but heres my thoughts.
1. you have have a front tire with tread seperation. sometimes you can see or feel it by looking at the tire tread. sometimes you can't see seperation only feel it in the steering wheel.
2. does it shake at certain speed? if so what speed? anything over 45 mph its possible the tires need to be rebalanced.
3. does this shaking happen when depress the brake pedal? if so the front brake rotors are warpped and will need to be inspected. they may need to be replaced or just machined.

A little more information would be helpful.

warped brake rotors

Check tires for broken belts jack up each wheel and watch for bulges and out of round. Also check suspension for any unusual play.

IF the engine was revving high RPMS it had to be a serious vaccum leak. If the PCV came undone it would cause it rev up quite high. the shaking was from the factory set RPM limiter when not in gear (around 4,000 RPMS) the only other vaccum leak big enough would be for the brake booster. They both have a check valve but that doesn't mean much. I would start there PCV is around 5 bucks and the other is about the same. If you need pics of location I could do that also.