1994, 92K miles, stock except for Bonez DP; car runs beautifully except for a wandering idle, as seen in thread title. Have set TPS, vacuum is about 18 in (Hg) at 700 rpm, and in fact have set idle with TEN/GND jumpered to 700 rpm. But nevertheless, a trip in town at normal engine temps produces stable idle speed of 1000 rpm for maybe 30 seconds, then drops gradually to 700. At next light, it's 700, at following light it's back to 1000, etc, etc.

Any clues?

 

I would try taking off your idle air controller (IAC) and cleaning it out. They can get dirty and not move freely to adjust the idle

I just removed mine and set the idle to 900, the idle stays around there and I don't worry about it.

 

How do you set the idle with TEN/GND jumpered.?
What do you use to jumper the two ?

 

All you have to do while the car is running is take a paper clip and bend it so that it is in the shape of a U. Then, insert one end into the TEN terminal of the black diagnostic box (located next to the driver's side strut tower) and insert the other end into the GND terminal. This is how to properly adjust idle because it puts the ECU into a "learning mode" while you adjust so it isn't fighting you and trying to adjust itself at the same time.

I have this problem as well. Mine is 900 sometimes and 1100-1200 sometimes. I am going to clean it out. Do you suggest carb/brake cleaner?

Trev

 

Mine does the exact same thing. Sometimes a tap the throttle realy quick and I find it drops from 1000 down to the 700 where it should be. Doesnt really bother me since it basically only sometimes idles 200 or 300 rpm higher than normal. Would love to find the cause if it's not normal though.

 

What are you adjusting when the car is on the the paper clip is in those 2 terminals?

Could this work also if you wish to run without and air pump? Could you have the car running put it in "learn mode" disconnect the airpump and set the idle so it idles fine?

 

Sure, theoretically. Why do you want to disconnect your airpump? The only reason to disconnect it is if your cat is removed. You are adjusting the air bleed adjustment screw located under the throttle body.

Trev

 

Well right now i have no intention of removing it.
But i did buy a new pulley/belt set up this past summer but had to replace it, because it required the airpump to be removed.. Before i got to work on it i tested how the car would run without the electric airpump connector hooked up. THe car ran very rough when it was warmed up.... So i was just wondering if i could possibly get that pulley set and re-tune the idle so it wouldnt stall when it was warm.....

Also does anyone have a pic of the Bleed Adjustment scree??? or what page it is on in the Owners manual? Is this screw easily accesible from plain site?

 

oh my god dude you better get your engine rebuilt!

lol only kidding, its not much to worry about though... annoying though.

Try loosening your throttle cable, it actually needs to be really really loose, much looser than youd think it has to be. Mine was too tight and i had EXACTLY the same problem.

 

Does any one have the pic of it under the hood or where and how it looks like b/c mines does the same thing and i want to clean it out too
Thankz

 

Attached is a picture of the Throttle Body from the 1994 parts catalog. If you look between the two lower mounting studs for the air intake tube, you will see a screw called "13-W76." That is the idle speed adjust screw. You will need a long flat-bladed screwdriver to reach it with the air intake tube installed.

 

Tired a couple of zillion times last night to attach that throttle body pic; all failed. No problem with uploading to other sites; trying again now.
Still doesn't work... the attachments page says it's uploaded, and it's a JPEG, should not be a problem... doesn't work on the "Test" web page, either. Tried re-creating the pic; same problem. WTF?

 

Finally, images are uploading again... repeating:

Attached is a picture of the Throttle Body from the 1994 parts catalog. If you look between the two lower mounting studs for the air intake tube, you will see a screw called "13-W76." That is the idle speed adjust screw. You will need a long flat-bladed screwdriver to reach it with the air intake tube installed.