i've heard and read in the board that vacuum leak causes rpm to go up and down every second but mine doesn't do that. instead, whenever i slowed down, whether i'm in traffic or approaching an intersection, and i press the clutch pedal before stepping on the brake, the rpm drops to 500rpm then swings right back to normal idle. there's once when it always drops below 500rpm and the car would stall on each intersection, but that only happened once.

right now, it just drops to 500rpm and swings right back to normal idle. whenever i slow down and step on the clutch. while stop, the rpm doesn't go up or down, although my idle is kinda low at about 650-700rpm it just stays right there.

from what i know, each time you slow down to make a stop the tach needle should drop to normal idling and stay there(correct me if i'm wrong) but i don't understand why mine goes to 500rpm and then come right up to normal rpm. can this be vacuum leak or something more serious? have anyone of you had this kind of problem???? really need your feedback here.

 

I don't believe you are having a vacuum problem.

There is a screw on the top of the throttle body that controls idle. Adjust that and set idle right and see if that works.

I believe it's screwed in too much where you are having the problem.

 

poison, but i've never adjusted the screw above the throttle body eversince i've bought that car. it has never been touch. can it tighten by itself due to age?


[Modified by _Endless_, 1:59 PM 8/24/2002]

 

have you tried cleaning the throttle plates?

 

nope, havent tried cleaning it. does the throttle plate got anything to do with it? how do you clean the throttle plate?

 

if theres too much carbon build up around the throttle plate, than not enough air can pass through, causing the idle speed to drop until the air control can compensate for it. you should at least try it and see if it gets any better. by some throttle plate cleaner or carb cleaner from and auto parts store. take off the intake pleneum, spray it in the throttle body and wipe it down with a shop rag. make sure you get in between the throttle and the body by opening the throttle with your finger. DONT SPRAY TOO MUCH cuz some of that stuff is pretty flamable and can damage your engine when you start it up. too be safe, spray it on the rag and wipe it down instead of spraying it directly in the throttle body.
P.S. USE A SHOP RAG ! not paper towels