I have a 1991 jimmy 4.3 V6 engine I have a problem that enre 1.500 to 2.200 rpm there is a vibration that can be the problem

Motor or transmission mounts are a possibility. Pop the hood and have someone rev the engine in drive with their foot on the brake (do it safely so you don't run anyone over). Does the engine buck up and down?

thank for the help, and I hope to solve this problem soon, the points of the engine and transmission are new feel the vibration in the motor car has been completely remanufactured, pistons 9.1, Cam / Lifter, Valvetrain, Hydraulic Roller Tappet, Advertised Duration 270/270, Lift .500/.500, Chevy, 4.3L, V6, Edelbrock intake, Holley 390 cfm, header, msd distributor, crankshaft balancing, and vibration is between 1,500 and 2,200, and tests done by separating the converter the engine and keep the vibration and thought that might be the crank or pistons

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If you seperated the engine from the torque convertor and still had the vibration, the only other external causes could be a cracked flywheel or a damaged harmonic balancer. I would be more suspicious of the balancer (unless it is new of course) since they can get damaged when pulling them off prior to the re-build. We actually had a case of that with one of our members in the last week or so.

will check the flywheel and well and also has one new harmonic balancer

Does the vibration happen when parked or only when driving? If it only happens when driving, you may want to look at a wheel bearing or even a front cv-axle, but cause vibration while driving that makes you think you have a engine/ tranny issue.

There are times that and thought that the problem is the rods or pistons I have another engine that is working on the same machine shop where the blocks were cut and installed a 40 pistons and connecting rods rectified