3.8 running badly

got DRL? lamps, daylight running lamps ? like they do up in Canada?
dash charge (gen, battery) warning lamp glowing"
if yes the fan belt fell off or Alternator gen, is dead.
the Alternator , runs power with engine running not the car battery
when Alt GOES DEAD, BATTERY DRAINS FAST AND IN 1HOUR
OR LESS ENGINE DIES, (PCM dies about 10vdc at battery weak)
or bad head lamp wiring, or bad DRL.

my scope will not reach your unstated engine.
nor can I do all the tests
find a second shop, get a second opinion.
there is no other way.

bucking has many causes.
1: spark bad. or that which creates spark CMP and CKP sensors.
even spark plugs, ever get a tuneup , like ever?
2: lost fueling, total.
3: ASD relay drop out. it sets codes but you just scan when it bucks. (many shops too lazy to do that and just guess)
4: loss of electric power. to EFI systems.
do head lamps dim at the buck or radio die. etc?????

dash gauges or warning lights?
any/either illuminated?
Never been a fan of removing cable for test, always relied on test equipment...
Do you have access to a volt meter?

I assume there's a problem with alternator. Check the grounding to engine, check continuity of a positive wire between alternator and battery. the energizing voltage should be checked as well. Might be the bad connection between battery and vehicle body grounding. Diesel cars are sensitive even in a little loss of connection and rust in the connection points.

get OBD code check then take it from there.

what engine?
fails hot engine, or cold engine and what engine of the many?
seems dont work in repairs.
ever do a tuneup ever?
sinces it sometimes runs we can check off bad engine. of the 4.
here they are. NO STARTS:
1: loss of 12vdc electric power to the EFI system. (dash lights dim?)
2: bad engine (skip this)
3: bad spark , seems is not an option here, we test all spark at all cylinders using a good new test spark plug.
Its a honda, and we check timing, too,, using , a timing light.
if the spark is good and timing is bad, then the timing belt slipped
if it slips more, the valve in the head bend. end of motor.
sometimes no starts, saves the engine, from itself. so i do spark 100% or better, on all honda's, i do a cylinder leak down test by hand
so i dont MAKE IT WORSE. (it's and interference engine)
4: bad fueling, flooding or starvation, readling spark plug tips tells me
which it is.

3.0L & 3.2L is Non-Interference , no engine stated. so ....

could be something with the ignition system, fuel filter. I would start with spark plugs, then wires, ignition cap, then fuel filter, ect.

Could be a bad alternator diode and it wasn't keeping the battery fully charged, which could be indicated by dimming lights, loss of power, or completely quitting when voltage becomes too low to properly fire plugs.

The squealing could have been a locked up alternator (probably caused by a bad bearing) and the drive belt is slipping on the drive pulley, making the squeal.

Hope this is of some help.

First thing to do is check all fluid levels, and top them up as needed, especially rad & oil. Have you checked owners manual for explanation ?

Your timing belt could be broken. You want to have this checked as soon as possible to prevent any further engine problems.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_62314e5b2470e8b5