Have you seen the threads about fixing the fuel gauges and the potential issues? 3 possibilities:
1) Bad gauge - touch the wires together and see if the needle moves. If is does, go on to the next item.
2) Stuck float - float stuck in the baffle and won't move.
3) Float filled with gas - replace float.
4) Bad fuse in baffle - follow instruction in the thread. It guides you through the repair with photos.
On 2, 3 & 4 the baffle has to be removed. I don't know the layout of the Speedster. It was a tight fit from our Challenger but it came out. You may have to loosen your fuel tank and tip it some for baffle removal.