While running errands, once on restart and once when putting in P saw the idle between 1000-1200...stayed there for a short time then dropped down to normal. Occasionally in gear it will drop from 7 to 600....random pronounced miss runs fine under throttle.

Also dash flickered a few times coming home last night, then went dark. Played with the dimmer switch then came back.

First items to check? no codes

Will pull the booster hose and try filling the intake w/smoke...suspect the wires are old but dont want to throw parts at it.

By the way where can I get those wire separators that fit on the metal stands that screw into the side of the head?

 

Flickered once or twice this morning, volts said 13.5 so figured all is well.
My numbers for the speedo are dimmer than the rest of the dash. This evening while parked gave it a rev to 3k or so and flickered once again.

Connection? Dimmer switch? Mice? lol

 

There is a light sensor mounted on your digital dashboard that fails after a bunch of years. Check out BATEE.Com for videos on how to fix your digital dashboard. Many issues are with connectors, they are all fixable. On my dash it was primarily the ground side that was needing a good cleaning.

Your light switch could be the problem but most issues start in the dashboard. The voltage of the battery does not have anything to do with the dashboard. One of the biggest reasons for problems is the simple fact that many of the components were designed with a 15 year life expectancy and my C4 is 32 years old.

Batee.com is the primary place for answers related to dash problems. He will either fix it for you or sell you the parts and let you do the work. When I did the fix I also upgraded the light bulbs in the dash so there is less heat in there anymore.

On your idle issue I would reset your TPS and maybe clean the IAC and go over your vacuum hoses for any leaks. A good cleaning of the throttle body always helps. It is likely one of the throttle body parts like the IAC that is causing your problems.

How old is your Oxygen sensor? If it is over 24 months then replace it, the signals get narrower and start to lag causing the ECM to have a fit.

If I had a idle function like yours I would start with a bottle of B&G 44K Fuel Injection System Cleaner before going too far. The 44K works very well and is powerful cleaners open partially clogged injectors allowing my C4 to idle smoothly. I have been told that I am support a Snake Oil. B&G 44K is used commercially every day to clean fuel injection systems because it works!

 

Thanks...I have an 02 sensor in the box no idea when it was changed last, 2 mos of ownership.
Ran a bottle of Lucas injector cleaner for the hell of it, they were replaced a few yrs ago (noisy as hell)
Removing the piece for the cluster and ligth switch pretty straightforward? Just my opinion these cars shake themselves apart lol
Any link to the idle reset or ck TPS havent done it since I had my 89 in 04. Thanks
Car needs very little but that stuff bugs me.