[daniel911T]

Brian,

I'm not going to claim to be a CIS expert, but I have worked a lot on Bosch L jetronic systems (the follow on to CIS)

In general, DO NOT TOUCH THE MIXTURE SCREW! unless the rest of the motor is in perfect tune!

Before going there, check the condition of your plugs, confirm your timing, make sure the vacuum system to your distributor is working as it should, make sure there are absolutely no vacuum leaks, and check for proper functioning of the various engine sensors. *edit* Also, especially if the motor has been sitting, remove and clean your fuel injectors if you can, if you can't, then run some good fuel system cleaner through the tank (many swear by the Berryman B-12 products.) Everything must be clean, properly set, airtight, and running at the right pressure before you touch any of the screws on the throttle body. Generally, the throttle body screws are intended to be set by someone with an exhaust gas analyzer.

The #1 most common problem on a CIS car is vacuum leak. Especially if the car has been sitting. The rubber on and around the engine will eventually dry rot, or just dry and shrink. Check all the vacuum lines, replace if they seem even a tiny bit iffy. Especially check the large diameter ones, and where they connect to the main intake. As others have said, check the seals around the injectors themselves. Finally, check out the short rubber tubes that go between the main intake manifold and the runners that actually go out to the cylinders.

The vacuum leak is what you should be looking for first. It's the simplest and cheapest fix. You can test the fix with duct tape, then order the new part.

Best of luck!

-Dan