Welcome! I lived in Plano for 12 yrs (just left 2 yrs ago). Forum members
"tomdietrying" and "Scott Harness" are in Dallas. Think those other two above are in Houston. I didn't have my VX in Dallas so I can't help much. Some find that a good private shop tends to be better than a dealership but that depends on if that dealership has any specifically Isuzu trained mechanics still on board.
Here's the remaining "authorized" Isuzu service facilities in Dallas:

CLAY COOLEY ISUZU
10849 COMPOSITE DRIVE
DALLAS, TX 75220
(214) 357-5700

FAZELI ISUZU
16200 LBJ FREEWAY
MESQUITE, TX 75150
(972) 270-2080

MANUEL ISUZU
8075 GRAPEVINE HWY.
N RICHLAND HLS., TX 76180
(817) 788-2994


For assistance locating an Isuzu Service Facility:
Owner Relations (800) 255-6727