Noticed some hesitation
 

I have a 90gt with after market wires 9mm and autolite plugs and everything ran fan but now when I go above 4k the car seems to sputter so i'm wondering do I need more spark or could it be a bad plug or wire, my mods are listend below but i'm pretty much stock nothing good installed yet.

If it's an ignition miss, it's more than likely the coil. Are you sure it's not a fuel issue?

I'm almost pretty sure its not a fuel issue although about a month ago ive been noticing a heavy fuel smell in the car after drivin about 10 or more min. mpg hasnt seem to drop and with my windows up I dont smell it which makes me think its a rear hatch seal lettin in the fumes, anyways I was wondering if I should invest in maybe aftermarket igntion system maybe just a new coil and new cap-n-rotor , I'm open for suggestions.

It's never a bad time to give an engine a tune up!

If your coil is original, I'd go ahead and replace it. It's going on 13, and it's tired. Try and find a crane ps91 if you can.