Was there an episode where Gordi gets promoted from Lt to Lt Commander?
Also why the was Harry Kim Ensign for so long?

No, Geordi got an implied promotion between the first and second season.

Kim never got promoted because his bitties weren't tig enough. At least, that's Braga's explanation. I don't think there was any official reason, and it was silly considering how many times Paris got demoted/promoted, but after a while it just became a running joke, so I guess the stuck to that. A fan explanation is that the lack of new crew members required them to maintain some command structure that significantly hindered promotions. Kim did comment once that under normal circumstances, he would have been promoted many times.

das

it's been answered, but I still want to throw my opinion in
geordi just got promoted in the background
kim stayed an ensign so that the positions could be kept the same, although towards the end he was given command of the night shift from time to time
paris got demoted due to disobeying orders, but was later promtoed back to his original rank

Don't see the point why Kim was kept back, would of been nice to see hiim as a LT. Man, star fleet must be pretty tough.

What I want to know is why was Riker demoted from captain after he took over the Enterprise and saved Picard's butt?

I always thought Riker's promotion was a temporary thing since the Federation was in a state of emergency at that point. My understanding was that Starfleet simply thought it best to have a captain in charge of the flagship and it had no time to appoint another replacement, so Riker was given the job temporairily.

riker only lost the rank because he decided to stay on the ent-d. he could have had a command of his own at that point

Another bit of info, if you hear someone refered to as captain, it doesn't also mean their rank is captian. It's just tradition to call whoever is in charge of the ship the captian. So... when Worf took the Defiant out on missions and Sisko stayed at the station, Worf would have been called the captian.

Was Tuvok LT Commander in the beginning of Voyager? Or was he always LT until he got promoted later on.

Didn't they keep changing it? some days he was LT, some days he was Lt Commander.

in "All Good Things" Data has Lt pips in the past when he is in engineering
I think tuvok was always an lt cmd. but the writers kept messing up the dialog

What the hell was up with Obrien? He goes from LT, transporter chief on the Enterprise to Ensign, Chief of Operations on DS9! During the later seasons of DS9, I think he was given a special pip.

That was a booger.

Harry Kim didn’t get promoted because he didn’t deserve it, just like he could never get laid on the holodeck.

I would say Obrien's case was just a costuming problem, but Riker does call him a lt in one episode.
I think he's supposed to be a chief petty officer the whole time.
enlisted ranks in trek aren't clearly defined

On Voyager, why do are tags different on the crew members ie, Lt Tores.

The differences on Voyager were due to the Federation/Maquis crew integration in the pilot.

He was listed all through out DS9 as a chief petty officer. In the TNG episode "the wounded" he was referred to as an Lt. Of course in season 1 or 2 of DS9 in an episode he calls himself chief engineer of DS9 not chief of operations.

Wonder why they never changed that, in the end they were all part of one crew.

You can thank Berman and Braga for that since they don't give a crap about the ST universe and well as continunity they in effect dug a hole so deep I doubt the franchise can get out of it.

Tuvok was promoted to LT Commander in the fifth episode of Season 4, which was titled "Revulsion."

Coincidentally enough, it was on tonight on the local Fox station.

watched a season 1 episode on TNN last night, Geordi got 2 promotions during the series, in season 1 he is a LT JG and by the time of Relics (which was also on last night) he is lt. cmd.

A few things:

1) several of the writers admit that O'Brien's character was handled rather badly. At the beginning of TNG he's just an unnamed crewman that they used, but eventually they created the O'Brien character because Colm Meaney was well-liked.

2) The rank pips were different between the Starfleet and Maquis crews to signify a battlefield commission. For some reason, this makes a big difference in Starfleet, but it shouldn't. Of course, the real reason might be to sell more replica pips to fans…

3) In a situation like Voyager's, promotions would have been frozen unless command structure called for it; there were no lieutenant commanders aboard after the ship found itself in the Delta Quadrant, which is a big hole in command. After his promotion, Tuvok's duties didn't change much. I daresay that most of the crew would have been promoted during this voyage if the rules had been followed, but that would have left them top-heavy with officers, and no "grunts" to do all the work. That has been the kiss of death to some military structures (i.e., the loyalists during the Russian Revolution - lots of officers, few troops. Ya learn something new every day).

4) Harry Kim didn't warrant a promotion for a long time (IMHO), but perhaps by the fifth season he had - Voyager's losses were mounting then, and there was more than enough room for a new lieutenant. It might have made an interesting backstory with him getting used to the new rank and responsibilities. However, I've heard rumors that Garrett Wong was difficult to work with, and for a long time stories with Kim as the central focus were turned down.

On a slight tangent, I've even heard that it was going to be Kim and not Kes, that was lost during Scorpion. The Borg Queen even mentions him by name and it's never followed up. I believe that they were on the cusp of firing Wong when People Magazine named him a "beautiful person" or some nonsense, and so instead Jennifer Lien was given the boot. She did have a pretty good sendoff with The Gift (essentially Scorpion Part 3, which, btw, forms one of Trek's best trilogy's ever), but then they gave her that episode where she came back and went all Carrie on them and basically raped the character.

Harry Kim was a worthless lump of human flesh and deserved to die.

And I'll tell you what else is wrong with Voyager, no true "Year of Hell." I'm talking 26 episodes of people dying, shit blowing up, and no frikkin reset button. They might have actually made a decent run of episodes if they had been forced to deal with those consequences.

That’s been my complaint with Enterprise all along. [OK, one of many.] Nobody freaking dies on Enterprise. Even when they blow the crap outa Klingons, nobody really gets hurt. Or else, if someone gets hurt/dies they just hit the time travel reset button.

So, this season they add some token Red Shirts. Big woop. Red Shirts, classically, have one or two lines before being zapped…

You ever notice that both Enterprise and Voyager have an infinite supply of shuttlecraft?

but with the Enterprise shuttles, at least in most of the episodes I can think of where one got damaged, it was damaged in a way that allowed them to recover it and repair it, unlike voyager where the shuttle would completely explode
if voyager had had a true year of hell it could have led to some interesting things, like bringing Delta quadrant aliens onboard as replacement crew