cost of timing belt replacement

The 2.5l or the 4.3l both have timing chains, and while the chain being broken can cause a no start condition, the most likely cause on either of those engines is a spark control or fuel delivery problem

could be timing or fuel usually with timing you will fell it crank fast the slow but with fuel should be around 50psi to start i think i correct on the pressure also cycle the ign.switch a few times before cranking as this will sometime build up enough pressure to start you can also hear the fuel pump hummimg you turn the ign on for about 5 sec.that will let you know if the fuel pump is working,one more way if it is the pump is while some cranks the ign is to use a rubber hammer and beat on the fuel tank this may or may not get the pump working but replace it soon because this may only w0rk a few times before the pump gives out completely...hope this helps you

There is no timing belt on a 4.3