rough idle

[4gotn]

my car idles high when my foot is not on the brake and when i hit the brake the car jumps between 1.5k and 1 k
its not the idle speed valve or anything
i already chedked
the lights also dim when i hit the brake
i was told by a friend that it may be the throttle position sensor...i doubt it though
any ideas??

[ariesdude]

bad alternator? The 4 brake lights (+3 center mount lights) take up a lot of power - it is noticeable especially if the headlights are on.

Other than that - the brake booster gets a vaccum line from the tb using a special hose. If there is something screwy going on there it might cause a vaccum leak that affects idle.

[joe 92mx3]

before you change the altinator put a meter on it.it should read 12to14volts at a idle try hitting your brakes see how much it draws my idle acts funny when i turn the wheel

[4gotn]

thanx for the replys ill try testing the alt tomorrow
btw
why was my thread moved to 4cyl....it have a 4 cyl but the problem isnt a specialty problem its just a general engine problem..i would have done better to have it on the general post where it was...admin plz respond