After stopping at a supermarket for a few minutes and then restarting my Rover, the engine sounded like it was going to tear itself apart; clattering like there were 10 loose frying pans under the hood. Turning off the key didn't help; the sounds continued. Dieseling?? Bad gas?? Timing chain bad and about to send a valve flying?? (Turning the key on again and then off finally killed the engine...)

 

If you are not mechanical enough, or know the truck well enough to determine what is wrong, do npt attempt to restart it, have it towed to your mechanic ASAP.
Let us know what you find.

 

Thanks for your input Mike. Strictly speaking I think your advice is right on.
However, after I shut the engine down, I went into disbelief about the noise I heard. So.......I started it up again.....holding my breath. It started up as if nothing ever happened. (My excuse was that I was on the way to meet friends for a day of hiking and didn't want to blow out the day. But I realize that I could have blown out the engine.....).
Anyway, it ran just fine all day....although I kept it under 60 mph on the hiway (mostly to make myself feel better).
It also restarted several times along the way without incident. Later in the afternoon, after coming out of a store (after a short visit), it did it again on startup; but less severe. This time it just sounded like the dieseling that you get when you shut a hot engine down sometimes...). I had never experienced this on startup however. The engine shut down right away with the key turned off.
After a short way, I tried it again (I'm ripe for risk)....and it started right up.

I'm suspecting now that I just got some bad gas.......and another confession......Because of the gas prices, my last few tanks were the middle grade rather than premium.......

I filled the tank with the best gas I could find and so far no recurrence.

I'll let you know the final outcome......

Keeping my fingers crossed.

Thanks
Steve

PS If you have more input (even if it's to say I'm a knucklehead), it would be appreciated.