Air Handler/blower motor is intermittent and acting weird

Hello! I'm having trouble with the air handler/blower motor randomly cutting in and out, or not coming on at all when set to cool. It happens in both the auto and on positions. The manner in which it cuts off and on is herky jerky and intermittent. It might cut out for a half of a second then run for 30 seconds then off for 10 seconds then back on for 5 seconds etc etc. Sometimes it is more like quick hiccups or a staggering, if that makes sense. It usually does this for a minute or two and then stops working completely. Other times it wont come on at all, and sometimes it will stay on as it should even with a few hiccups at first. It starts cutting in and out immediately when turned on even when it's been off for days. It does seem to come on and blow as it should on a call for heat however. I only tried the heat once though, because it was a very humid day and already a muggy 81 degrees in the house, but it worked at a time when it wouldn't work at all on cool. *Other info:* The compressor and outside unit turns on each time as it should. I always change the filter regularly and it has a new one in it currently. The capacitor for the blower motor is almost a year old. The thermostat (basic big box digital Honeywell) is a year old with brand new batteries and it is properly wired (4 wires R/W/G/Y) with seemingly good connections at the stat and furnace terminals. I haven't jumped the wires at the thermostat as of yet. Mainly because I don't want to blow a fuse, transformer, etc., if that's possible, and then have double the troubleshooting work if I could've just ruled it out with a meter to begin with. The thermostat face uses pin connectors to connect with the sub-base/wiring, and the switches/controls are on the face only. So there's no way to check any readings with a meter at the thermostat itself while in a call for cool or on setting, etc. if that is even necessary. So, could it be a bad thermostat, bad stat wiring, bad relay or board? Maybe a weak motor or other? The unit is a 23 year old Goodman that has little to no info for it on the internet. If anyone can pretty much tell what is wrong by my description, or could give me a rundown on how to troubleshoot my way to the culprit, I'd appreciate it greatly. I'm in the south and it could turn 90+ degrees at any moment now. I am comfortable with a meter and electricity, live or not, btw. If you need any other info I'll gladly give it. Thanks!