I have a goodman furnace. I can't tell you the model number as I'm at work but I do know it's a 80% efficient furnace. For the past month I've been having issues, it started as 3 blinking lights LED and is still that way now.
The furnace receives the call for heat and the motor starts up, I then hear the little snick from the pressure switch but nothing happens after that. The motor just runs for a min or two then switches off. If I turn off the unit for a while it will reset and run as advertised when turned back on but seems to cycle off a couple of times when trying to get to the desired temp.
I have changed out the Pressure switch, both limit switches, and the inducer motor. I've gotten on the roof and checked for a clogged vent but it was clear. Also I have checked the tube to the pressure switch which seems fine. I have PVC pipes running out the bottom of the furnace but I am unsure what they are for as they run into a section of the furnace that has some different type of tape sealing it.
Any help would be greatly appreciated.

Did you clean the orifices the tube connects too? Did you clean your flame rods? Take a few minutes, an hour maybe, to review these videos and let me know if that helps any. Also Google "how to troubleshoot a Goodman furnace. Techs spend many hours getting classroom and hands on experience in instructions to be certified, so don't expect easy result since most times it requires a process of checking components thoroughly, and knowing how they function. Just changing parts and failing to solve the problem is frustrating as you have found out.

Start here there are many to follow.

https://www.bing.com/videos/search?q=3+blinking+light+on+goodman+furnace&view=detail&mid=777EC75F91C68943C55A777EC75F91C68943C55A&FORM=VIRE

Thank you for the reply. I will review the videos asap. My work PC was acting up and not allowing me to type more than one letter per second earlier, but I have also cleaned the tube going to the pressure switch and removed and cleaned the flame sensor. I will add that when I cleaned the flame sensor the unit worked for approximately 3 days before messing up again.