Plot hole: For the past 5 series, Bulk and Skull have been in every episode. They've seen villains from other galaxies (Lord Zedd, Rita Repulsa, The Machine Empire, and Divatox) who have all sent monsters to Angel Grove and threatened Bulk and Skull on countless occasions. They've even been turned into monkeys and made invisible by space creatures. Why do they feel the need to spend Series 6 seeing if alien life exists? Surely 5 series worth of aliens is enough proof?
Plot hole: During the Green Candle, in series 1, we are told that the only reason Tommy's Green Ranger powers could be drained is because he touched a special wax. However, Kim, Billy, Zack, and Trini did not touch the special wax, therefore the candles shouldn't have stolen their powers. When they were captured, they were transported straight to a prison cell as Goldar lit the candles, therefore the Rangers couldn't have touched the candles when captured.
Plot hole: In this episode Globbor's energy is drained when Alpha stops the Solar Eclipse, and his Energy drains in the sunlight and severed the physical link between him and Ninjor. This is strange because in the previous episode Globbor had no trouble fighting in the sunlight, and the link stayed intact in the sunlight.
Plot hole: Quite often the Rangers were contacted at school and would teleport to the command center, danger zone, etc. It is safe to say that the faculty would notice star pupils missing classes so often, yet it was never questioned or addressed.
Plot hole: Tommy states that he and the other Zeo Rangers destroyed the Machine Empire's leaders and ultimately destroyed the Machine Empire except for the Generals who escaped. This is not true - Lord Zedd and Rita destroyed the Machine Empire leaders at the end of series 4, and the Space Rangers destroyed them again in Countdown to Destruction in series 6. The Zeo Rangers never destroyed the Machine Empire.
Plot hole: Andros leaves the Shuttle on the remote planet, then later returns. Not long after the Astro Megaship lands, it is attacked - the Rangers quickly retreat and take off. The Rangers could not have formed the Astro Megazord later on in the episode, as they left the Space Shuttle on the remote planet (the Shuttle serves as the head of the Astro Megazord).
Plot hole: The whole "reverse time" thing is messed up. Master Vile claims that everyone has been changed back to children. So where would the adults we see for the remainder of the series come from? The Rangers are all about 20, and they're turned back into about 10 year lords. Why is Lt. Stone turned back approximately 30 years, into a 10 year old? It can't be that the reversal was different for each person, as Master Vile claims everyone is a child again. Very confusing.
Plot hole: In the first episode of series 4, we are told that the Power Chamber was directly below the Command Centre. In Hogday Afternoon, part 2, at the end of series 3, the Command Centre was completely destroyed - so how could the remains of the Command Centre be next door to the Power Chamber?