Why does my fiero start ok then stall right away? It will not stay idling. So far the sparks and wires have been changed or checked but this has not helped. A tune up has not been done because it will not stay running long enough. What else could I check?

What year and engine? Carbed or FI? Is the check engine light on?

The MAF sensor, which is right after the air filter could be at fault. If the air filter has recently been changed, the MAFs electrical connector may have been left disconnected. If it has an MAF, have it cleaned with MAF spray cleaner.

The fact that it starts okay suggests that the ignitoin system is working. That would lead me to look at the fuel delivery.

Assuming this is carburated, as I suspect, then it’s possible that the float bowl is filling and the spray from the accelerator pump is providing sufficient richness to initially fire the engine. That would suggest that the fuel pump and accelerator pump are both working. From there I’d want to check the choke and the high idle cam. Those are the most highly suspect areas IMHO. Without continued rich mix and/or elevated idle, the engine will die when cold.

Prop the choke open, prop the throttle plate open, peer down the hole with a flashlight. Manually activate the throttle linkage quickly and look for a spray of gas. That would confirm my guess that the fuel pump and accelerator pump are functioning.

Post back with your results.