The thread chaser did not go in very far...it is a bit puzzzling! The mechanic made a house call to put the time sert insert in and when he cut out the new whole substantial metal shavings were present...before inserting the time sert he turned the engine over to clear out the hole...I am pretty confident he did a good job...unfortunate the vehicle is still running rough...with no or very little compression in the 4 cylinder.

41 posts so far in this thread.....Does this car have a sunroof? How many pedals are on the drivers side floor? It is very simple to put the car info in your signature line.
If indeed there is low compression in #4 what is the actual pressure?
I don't care what a mechanic 'thinks', just facts are what's needed for a correct and accurate diagnose.

To check for a valve leak, rotate the crank to TDC; [#4 & #1 will have closed valves at that point] insert a tight fitting rubber hose in the #4 plug hole and BLOW hard into the cylinder.
Listen for air leak thru the intake/exhaust.

Back to the original problem....did the car only stall/die after warmed up? That question was never answered.
Facts are needed for a correct and accurate diagnose.
If I knew the car was Carbed or Fuel Injected I'd be able to come up with a few more ideas to check out.
You don't really need a multi meter for this car, a simple cheapo test light will work for almost everything you'd need to check.

low compression........
 

this 89 Honda Accord is carbed...The car stalled after running for a considerable lenght of time...starts and stops....or over 65 mph (when it gets hot). This "low compression" or no compression problem is a new problem that occurred after messing with the spark plug..using a thread chaser...and finally installing a time-sert insert in the hole to repair cross-threaded spark plug hole...I am not a mechanic..have no testing ability...just was told that the thread chaser may have nicked the valve if it was down...causing a the valve to not work right....just not sure what to do from here....we want to sell this vehicle....this car has no sunroof and it is an automatic.....do we need to have a compression test on the vehicle...

Rent a compression tester, you get your money back when you return the tool.

It should come with instructions on how to use it.

Post the results of each cyl (1 thru 4) and we can go from there.

Last, you have a DX or LX (carb). If it has power windows then it is an LX....:)

EDIT: You had some sort of ign problem to begin with (IMO), did it "grow" up and now seems like a compression issue....?

Well go grab a giant spoonful of flour from your wifes cupboard, with #4 spark plug in the hole....sprinkle the flour around the base of the spark plug and new timesert.
then crank the engine over and watch for a puff of flour to go airborne.
Let's make sure the plug/timesert are okay.
I'm having a hard time with the idea of a tap hitting a valve edge, just by way of the angle of the plug hole in the head.
Now that being said; What I have had happen in my lifetime, is that a metal chip from fitting a timesert hung up in the valve seat and held the valve open slightly.
A valve clearance check will tell that story; It might be possible to "blow" the chip out by way of a max engine rev.

Cool, didn't think of that one......How have you been? PM me when you have a chance.