Hello,

My 93 C2 which I have owned for less than a year developed it's first 'issue':

On the way to the grocery store I notice that the idle is dropping very low and then bouncing back up to 1000 rpm before settling into a lower than usual idle of about 700rpm.

After starting the car at the grocery store parking lot for the drive home the Check Engine Light is on. Idle is still a little low.

I understand the ISV might need to be cleaned, but in searching through the threads on low idle issues I did not see any correlation between the ISV and the CEL coming on.

Does anybody have any suggestions?

I have no records from the PO so I have been planning on taking the car in for a major service (Valves, belts, plugs etc..) Maybe it's the car's way of telling me that it's time for a tune-up...?

 

See what error code you have first: http://members.rennlist.com/billwagner/CheckEngine.html
...and go from there.

 

When my idle was erratic, my check engine light came on but there was no code thrown (not sure how that is possible....) It would come on without the primary indicator light coming on.

After cleaning the control valve, everything was fine

 

Take a look at this thread, may be of help. https://rennlist.com/forums/964-forum/426276-engine-will-not-hold-idle.html

 

I hate to have another pop at the much maligned DME relay, but your symptoms are almost identical to those I suffered just prior to my relay giving up. ... if you do carry a spare, worth a go just in case.

 

UPDATE:

It was the ISV...I took a look at the 'canister' and noticed that there was no clamp on the hose nearer to the back of the car. I decided to go ahead and clean it out though. I could not figure out how to undo the factory hose clamp but managed to wiggle it free.
I sprayed out the ISV with Carb cleaner and WD-40. The internal valve seemed to move a little easier after doing this.
I put the ISV back in, started the engine and revved it a few times the CEL light went out and the idle seems good.
I have to go into work for a few hours this afternoon, so will do a proper road test to make sure all is well.

Thanks to Rennlist and everyone for the advice!

 

UH-OH:

So on the way to work the CEL light was on again and the idle still drops low with the clutch in and the engine is idling slightly unevenly.

I did the engine code as suggested above by "ilko" and got one code:

Code 1222 - Idle speed control activation

Is this still the ISV not functioning correctly or something else?

Thanks again...

 

Went for a drive yesterday with the family...Car was running and idling normally at about 800 rpm, but the CEL light was still on. I disconnected the battery for about 45 minutes and reconnected it but the light was still on, however now the idle is a little above 1000 rpm? I checked the fault codes and did not have any.
Do I need the proper reset tool (hammer) to be run...?
Will drop by my mechanic the afternoon and see what he says.

 

Sorry I can't help, but please tell us what your mechanic says. Sounds like a frustrating issue.

 

Strange to see a CEL and no fault codes. Do keep us posted on what you find.

 

Idle was back to normal today. And the CEL light was still on.

So I dropped by the garage this afternoon, my Mechanic said he didn't have the computer to hook up to my car, but he took a listen to the engine and jiggled a few things and now the light is out...He didn't even realize that he did anything, it was as I was driving off that I noticed the light was no longer on. Puzzling...

I have an appointment for a tune-up in a few weeks as I have no records from the previous owner as to the last time one was done.