I just cold started my car and it started right up, but after it started it slowly turned off. It appeared that it couldn't catch a steady idle. After it turned off it just kept cranking until I applied the accelerator a little to turn it back on. Anyone know what it could be? Thanks.

 

Some more info would be helpful...year/engine/fuel delivery system/modifications, etc.

 

86 305 TPI stock.

 

Any check engine lights?

 

No light or codes

 

Check the simple stuff first

First stop is fuel - Check the filter, flow and pump/pumps, If its starting and then dies i would be thinking something to do with starvation
Next stop - I would go with vacuum leaks, the bane of any Thirdgen owners existence. So many to check, so little time...
Third stop - Spark, Plugs and Leads, Distributor cap etc. id call this one the least likely as it does start. However if youve got spark breaking down for any reason this could be the culprit. Look for screwed plugs, cracked leads and any cracks on the coil. check the inside of the distributor cap and rotor for burnout/wear.
Fourth stop - The exotic stuff EGR, Computers, Sensors, Etc. This is where the higher end pain in the **** troubleshooting comes in.

Enjoy