Yay, old cards make me feel like a kid again.
Actually, this card is pretty bad. Unless you have a good retrieval system for your energy, it is gonna burn (lol) through your source pretty quick. Even with dble colorless, this baby isn't going to be able to attack more than twice in a row before you have to wait to power it up again.
Of course, cards newer than gym which i have no knowledge of may solve this problem.
Weakness it bad, resistance is good, if a little boring, retreat cost is high considering you might want to switch it around to recharge. Loses badly to rain dance, which comes up quicker, as classic fire decks tend to run charmeleon over breeder, probably because charmeleon is actually better than charizard in many cases.
Energy Burn was nothing to write home about in classic format, but with some of the newfangled energy that seems to befloating around recently, it might be better, i don't know.
In general, if you are playing this line at all (in classic), you are probably playing red aggro or that weird fire/water build, and would thus probably be better off just sticking with base charmeleon.