ok my car will idle fine when cold and warm. Sometimes for some reason when I start after it is warm my idle will drop then rise drop then rise. I rev it to like 2000 and let it drop a few times and then it will go away. My car idles at 1000 when warm and at 1500 when warming up. Today is the second time it has done this to me. All I did was start my car let warm up then go around the block then to a back road to step on it. I parked the car and went inside came back out later started the car and it started doing it. O yea when it does this I hear a kind of sucking/choking nose coming from the throtle body. Or thats what it sound like.

 

Sometimes hot starts like to mess with these things...If after "blipping" the throttle, she seems to settle down a bit, and then runs normally after that, it's really not a problem- just an aggrevation...

If you'd like, you can test your BAC valve, pressure regulator control solenoid (for the hot start assist sytem), and air bypass solenoid per the FSM (or Haynes) just to make sure...

 

you've got yourself a vacuum leak or two or more.

hugues-

 

ok thanks ill check into that stuff I am going to check my acv blockoff also plate it rattles loose sometimes. Another question is 1000 rpm a normal idle spot. I ask this because before some of my mods my car idled lower like 800 were some say it should be. Should I worry about this or no. It seems like I would save a little gas with a lower idling car but then again I have no idea what I am talking about.

 

the normal idling speed is set at 750 rpm with initial set coupler on. so, in real life, it may be a tiny bit higher. 800 rpm would probably be about right.

1000 rpm is too high.

If you can't set the base idle speed according to the FSM, which usually means you can't get it to go down to where it should be, you have a vacuum leak.

hugues-

 

Yea I tryed to set it but when I remove the jumper and start the car it does that thing I was talking about and then goes back up to 1000. It just started this because it never did this. O and when I would give my bac a tap with my screwdriver the Idle would go down. I guess I am on the hunt for a vac leak. thanks o yea It got a little better when I moved my injectors a bit so I guess thats one now just got to find the others. I guess ill be hunting for vac leaks today thanks hugues an 88

 

ok I found were the problem is its the bac valve. I unpluged it and started my car and the idle went to were I had set it. On the top of the dynamic chamber were the hose for the bac is there is a bulge in it so im thinking maby it is clogged. Or it might have a vac leak somewere. I also had some unfinished business with the acv blockoff plate. I dident cap or even unplug the two vac hose that connect to the block. Anyway I unpluged them and caped them off. The idle only goes down when the bac is unpluged so I need to see what I am going to do. I am going to try and clean it first and if that dosent work then I will remove it. Anyway thanks alot guys for your help ill let you all know what I end up doing.

 

ok the bac valve gasket was half gone. now I know what that sucking noise I was talking about. It was massive air going through the bac valve. No more pulsing idle and good idle speed. Runs like a champ now all because of a bac gasket. Thanks again for all your help!

 

Just curious, RTV or an actual gasket?

 

Just a gasket and nothing more. I guess im lucky I have never had problems with leaking. I also have just a gasket on the thermostat that my dad said would not work. Well I got ten bucks that day.