1999 rough idle then oil pressure drops to zero

[MoonieGT]

If I'm driving around the car is fine. However, when I come to a complete stop the revs drop down below normal idle and the oil pressure drops to zero and then pops back up? The car runs normal except for that. Smooth power all the way to redline. Here is a link to a video of my pressure gauge so you can see what I'm talking about...

http://www.youtube.com/watch?v=LKgBRYNou_c

Any ideas?

[Radio-Active]

Unless you changed the unit, the oil pressure gage is only a fancy idiot light. I would make sure you have oil on the dipstick.

[tailchaser]

Start by checking the ground strap. If electrical issues aren't immediately apparent, it would probably be wise to verify that the oil pressure is ok before doing further troubleshooting, as it may mean your oil pressure really is dropping below the 4 psi threshold in the idiot sensor, which would be bad...

[MoonieGT]

Ok so the car has been consuming oil and was LOW... So the oil pressure issue is solved, but I'm not sure how it consumed so much oil... I need to keep a much better eye on the oil apparently...

The idle issue is still there though. I'm going to pull the plugs and take a look at them, but since the runs fine other than idle that's probably not it. I think the coil packs were replaced in the last two years. What else causes the revs to drop at idle. Scratching my head here because it drives perfect...

[sammm]

The infamous '99 idle droop.

http://forum.miata.net/vb/showthread...light=idle+dip

[MoonieGT]

That sounds VERY promising. Thanks! Now I just need to find the time to do it...

[MoonieGT]

I pulled the idle adjust screw and cleaned it and the passage. Idle is now smooth :)