1993 s-10 blazer-vin Z When engine is turned off , engines shakes or shutters for about 2 seconds- Starts up smooth, idols and runs smooth. Have, new wires,plugs, rotor and cap. Timing is set. What can cause such a brief shake? It is a rough shut down! It is very brief, when I say about 2 seconds, that is how long it is, never longer.

 

usually the older cars would do this due to off timing or a really high idle. if your truck is idling high that may cause it. i remember having a old beater truck that would run for about 2 minutes after shutting it off. if i shut it off in gear though it wouldnt do it. thats not really a fix but might stop the shake

 

Try running some SeaFoam through it. A buildup of carbon deposits can cause hot spots that will ignite any fuel vapor left in the intake, runners, and chambers. Just something else to consider.