[07Versa6MT]

Did you check all your relays and fuses? Could be an ignition control module fuse, which will cause a "no spark" condition... Anything unusual happen before this? Had to boost it recently? Unfortunately you can't check for spark in these things very easily as there's no way to pull any of the plugs out. I guess you could check for a voltage pulse at the most easily accessible ignition coil plug to check for spark. Checking fuel pressure at the rail is a no brainer at this point, bad regulator might cause a complete no start, but usually they go gradually to my knowledge. You can sort of isolate a fuel problem if you cycle the key on for 2 seconds then off and on again then try starting it, if it runs for a little bit then it's probably that regulator. The fuel pump will usually power up for about 2 seconds in KOEO position (key on engine off) to build system pressure then shut off, if it isn't holding system pressure then that's your problem. So try cycling the fuel pump on and off, or even jumper the fuel pump relay to power it indeffinitely and try to start it. Not sure if the Versa's electrical system will allow the fuel pump to be run all the time though. IPDM might prevent that. Worth a try though.

 

[07Versa6MT]

Whether they found internal engine damage and deemed repair necessary is irrelevant to the starting issue. That would not cause a no-start or intermittent no start. I would be asking to talk to the mechanic(s) themselves who typed the diagnosis into the computer in the first place, and ask them what they did to confirm their diagnosis. Did they do a compression test and found the bad cylinder? Did they use a borescope to look inside the cylinder and find out that way?

Just tell them to figure out your no start issue. If it's just a simple matter of fuel or spark, it isn't that hard to diagnose those problems. A simple 5 minute fuel pressure check would eliminate one of the possibilities.