89 maxima speedodmeter problems

[89turbomaxima]

i have replaced the speed sensor with a brand new and my speedodemeter with read when i put it into first gear and just barely start to roll it starts to read 15 mph and will climd to 45 then no higher my cruise and every thing else still works but when i go alot faster it will drop back down to 0mph. so wat the hell is wrong do i have to replace the whole cluster or does anyone know a simple way to fix it.

[MinisterofDOOM]

Either your new speed sensor is bad or there's a problem with the gauge cluster itself. Bad gauge clusters aren't too uncommon in the third gen.