O2 Sensor solves idle, but causes other issue.
 

My '82 SC came without a cat & O2. I am in a no emissions state. Car was running great last year, but this Spring the idle started to hunt and the car would sometimes stall if I blip the throttle at idle.

Asked my shop to look at it and discovered PO did not install an O2 sensor in the bung of the SSI's.

Shop put in a single wire sensor so he could check/adjust the mixture.

Car now starts great, and idles right down after a short warm up; but I find that at 2100+/- RPM, (you know 3-4th gear cruising around town) which I do so often the car seems to hunt a little with the revs going up and down. Since the car is moving in gear I think the hunting is actually masked a little bit.

As I said the car starts, accelerates and generally runs great except at this RPM range.

I was thinking of unplugging the 02 to see if it changes.

Any comments?

Thanks.

After 100 miles of driving I definately feel the slight surging at 1900-2100 rpm.

Kinda annoying.

Anyone have any input?

Thanks for your help.

Surging is usually a vacuum leak. Tach surging/bounce can be sign of an alternator/regulator about to go tits up.

I used to have surge once in a while when it get way too hot. There were 2 things I did and it's gone. 1- change spark plugs from platium to the famous copper NGK. This also got rid of the missing once in a while when it's too cold/wet. 2- my buddy played with adjusting my idle adjustment screw.

I tend to doubt it's vacum, as it started right after we installed the 02 & set the mixture.

Car idles perfect and runs great otherwise..

Pull a plug and see what's what.....platinum plugs suck. For kicks and giggles, throw a meter on the battery posts....

that's what you get with the sensor connected. annoting isn't it? the original surging/dying at idle was probably just a too rich initial idle setting, and maybe a too low idle speed. shoulda tried it at 3% CO @ 1000 rpm idle.