my 1999 z24 with a 2.4 twin cam dies at idle what are some of things that may cause this?

Is car skipping?If so you may need to change your plug,s and wire,s,If not then,may need to clean your throttle body,and may be some fuel treatment.

No plug wires on these. The Quad4 through TwinCam had the coils mounted to the bottom of the aluminum cover above/between the DOHC towers. There are a few common problems with your 2.4 TwinCam that you can check. Is it showing a check engine light. If so get it scanned, that will save sometime. Does it smell like it is flooding - over fueling at idle before you give it throttle and or is the motor sputtering/shaking. This is the most common issue and is usually caused by weak spark. If you have this issues you will need to inspect all the components under the above mentioned aluminum cover. The weakest link is the plastic housing that bolts to the bottom of the cover and houses the ICM, coils, leads and integrated boots. If it is cracked or warped it needs to be replaced. The foam must hold the coils to the cover to allow for a good ground and the ground strap must be in contact with the cam tower between one of the rubber isolators on the cover when in place. Usually it's an issue with the plastic cover, on this system if one component fails in the loop 2 plugs, 2 boots, 2 leads, one coil you loose 2 cylinders. The small plastic pieces on the boots sometimes break but I have had no issues there. A lot of people are converting to a regular 4 cyl coil pack and running spark plug wires to eliminate the above parts. If it runs good but still smells like fuel look for a stuck injector. If you pull the plugs to check spark you will notice fuel residue if an injector is open! I haven't had a crank sensor or ICM go on any of these cars that I have worked on yet, but a possibility. You can pull the entire assembly pull the plugs from the motor and install on the boots and ground the cover and plugs and visually check the spark. If there is not fuel smell follow tennisshoes's advice with the IAC. Check the throttle position sensor also. Good luck.

Correct, idle air control valve or motor, or gas pressure regulator, easy, also if speedometer does not communicate, when you stop will happen, if manual, do not know If automatic .