rough idle....

[dindy]

hi guys its me again. got a 2001 , 1.0 automatic vitz. i got little bad issue with idling. on start up it runs good. on drive reverse and other still no problems... but as i come to a stop sign and i press my brakr to hold the car, it begans to shake roughly. then i shift in neutral and the rough idle smooths out, but not that smooth....still i get rough idle even on neutral with the ac on. no check engine light. due 6 about 1 year ago, i had idle control valve and air flow meter trouble...chnged them to original part, engine light went off, but still rough idle....mechanics keep telling me it is normal, but for me not. my car never did that before. it driving me crazy..so anyone had similar trouble? jus t to tell you

new idle control valve
new air flow meter
new air filter
new plugs
oil changed, trans oil changed, water coolant changed.

any help pls, before a change my car now. thanks :)

[CTScott]

Try pulling up the emergency brake lever and taking your foot off of the brake pedal to see if the brake booster is leaking with the pedal all the way pressed.

[dindy]

tryed that ctscott. you told me last time about that. it will elimate the rough idle about 50 % but still i got rough issues... i tooked my brake booster for a check up. mechanic says nothing bad with this.

[CTScott]

Since you live in a country with a great amount of salt in the air, another thing that may be worth checking is all of the grounding connections under the hood for corrosion. Also, it may be worth popping the cover off of the ECM to see if it has had any salt damage.

[Foot]

I know at idle my car constantly will range from 500 to 800 rpm. When it reaches 500 rpm you can feel the car giving the engine a little gas giving a shudder pushing the rpm back to 800. This will happen a few times a minute when at a stop light. I was told this is normal for my car, maybe it is normal for yours as well.

[dindy]

sure got no salt under my bonnet, i like my engine bay clean :) but i checked that out. no corrosions on wires. and no corrosion on battery terminals. even checked my interior under the dash, and rechecked the ecu wiring too. i will hook up my rev counter later on to see what readings i will get. i had allready checked my engine with a vacuum gauge. it seems ok. but im thinking , can it be a mounting?