I am having a few issues with a 98 TK and whenever the car changes gears it revs quite high before dropping back to normal. The car also drops in power every now and then for a few seconds and the lights dim etc.

I had an auto electrician check it out on the Weekend and recondition the alternator but it didn't seem to help. Anyone have any ideas on what this could be?

Auto? sounds like there is a problem with the gearbox to me...

If the transaxle is revving out between shifts, then the band is slipping against the drum. Rebuilding it is pretty much the only sure fire fix.

Sounds like u might be better off finding a 2nd hand gearbox. Or, try disconnecting the battery for half an hour os so, so that the computers can reset then take it for a drive.