having an issue with my car continuing to run after i turn key to offf position.

After a few seconds it wants to shut down but it just seems like there is something trying to keep it going i guess its still getting spark should i change out ignition switch?

i did just change my alternator and spark plugs and wires not for this reason but because they were bad and yes car was not shutting off prior to these fixes

any ideas?

 

Carbed?? Or efi??
Is your timing set correct??
Any vacuum leaks???
What rpm is your idle set to...

 

Dollars to donuts it's a carb'd car.

It's really rough after turning off the ignition, right? If so, no, it's not still getting spark. It is still getting fuel, though, and hot spots within the combustion chambers are igniting the fuel/air mixture that is still flowing through the engine.

Usually when this happens there are either excessive carbon build-up in the chambers, or really rough castings that are getting hot and staying hot enough to continue to ignite the fuel/air. Often this is accompanied by a poor tune, with excessive ignition advance, and/or excessive carb idle opening. Sometimes running a product like Sea Foam through the engine will clean things up and stop the problem. But, make sure everything is set to factory specs first (timing, idle speed, idle mixture, etc.).

 

Yea its carb 1986 z28 lg4

 

I have to check timing and idle speed but I guess it wouldnt hurt to use sea foam to clean out some carbon right?