Feels and sounds like it is missing -starts with no problems runs rough usually every gear(1996-5-speed) Could it be a vacuum hose--How do I know?

What were the plugs gapped at ? Check for loose vacuum hoses and electronic connections as well .

Sounds like a vacuum leak. Spray carb/throttle body cleaner at all fuel and air intake areas ie; intake manifold to heads, throttle body to intake, all vacuum hoses, etc. Work the throttle to keep it running or have someone inside doing it. You will know if the carb cleaner gets sucked in somewhere. That will be the location of your vacuum leak.

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it sounds like transmission problem with that problem you should have a trouble code storeed in have some one scanned for you that will tell you the problem, also check for vacuum hoses one may be disconnected or cracked

Sounds like possible vacuum leak. Next time it starts try spraying starting fluid around vacuum hoses, if engine speeds up, there is a vacuum leak at that point where you sprayed. Hope this helps.

That sounds like a brake booster problem. The brake booster runs on engine vacuum to help make the brake pedal easier to push and easier to stop the tahoe. When a booster develops an internal leak, you can hear the vacuum escaping through the leak when you step on the brake. The engine stalls because the vacuum leak in the brake booster also causes a large vacuum leak for the engine.

To verify that this is actually the problem, go outside the vehicle with the hood open. Find the large brake fluid reservoir attached to a large round metal black (usually) canister on the driver's side of the firewall. (back of the engine compartment.) There is a large black rubber hose pushed into the top of the black canister, which is the vacuum line attached to the brake booster. Pull the rubber hose out of the grommet on the booster and stick your finger over the hose. Have someone start the tahoe. You will feel a considerable amount of vacuum pulling at your finger, and if you take your finger off the hose, the engine will stall. Also have someone step on the brakes while your finger is over the vacuum hose. If the noise is gone then you know the problem is in the brake booster.
Don't forget to re-attach the vacuum line to the brake booster. Failure to do this will result in the engine running very rough (if at all) and the brakes will require excessive effort to try to stop the tahoe.

Rough idle is usually a symptom of a vacuum leak especially if the engine runs good at full acceleration. You have 14 year old vehicle, so check all under hood vacuum hoses.

missing at idle and good at highway speeds typically means either leaking injectors, vacuum leak and/or base engine concerns

I'd start with the injectors

the best way to find a vacuum leak is to buy throttle body cleaner as it is combustible, if you spray around the hoses and manifold base and you see that the engine idle goes up or down you have found you vacuum leak. a lot of times on old cars, the hoses start deteriorating with age and heat.

Well it sounds like you've started to do your "due diligence", but there are several things left out. Your problem could be many things. Something as minor as a vacuum hose left off, loose, or in the wrong place. And just because you changed the plugs and wires, don't mean you fixed your problem. Open your hood at night and see if you have any sparks "dancing" around. Another way to check this is to open your hood and spray a soapy water solution on your plug wires and look for sparks jumping around. If so replace your wires. You didn't mention what type of wires and plugs you used. I would reccommend NKG platnum plugs and a Bosch wire. I know this from experience,(the hard way teacher). It could even be the gas you are burning. I've owned a lot of Vettes, and I am the kind of guy who believes they should be driven. If not it's like having a beatiful wife and never taking her to bed.I know a lot of people who only drive them "once in awhile". Sitting in thier garage can cause many fuel problems, condensation, sludge in the carb, or filters etc. This can all lead to the problem you are describing.
Low speed miss- usually plugs
High speed miss- usually wires or valves
intermitten miss, fuel or electrical.
I hope I gave you some places to look to find your problem.