Blinks 8 times and my manual only goes up to 7 blinks

Kill the power to furnace, after a few minutes, turn it back on,, watch the blinking lights and count them again,,

Done that, still blinks 8 times. It starts with 2 clicks from circuit board then flue fan comes on for about 3 to 5 second then shuts off. No heat bar no nothing

Code 8 means an igniter circuit problem. So basically, you have a bad glow plug, or a miswired glow plug, or a bad control board. NIne times out of ten, it is a fualty glow plug (hot surface igniter). Check the glow plug for continuity, if none, its shot. Goodman/Amana added codes 8,9, and 10 a few years back, but it was a real pain trying to figure out the codes before they revised, as a code that isn't shown in the book made many people think the control board was fualty when it wasn't. Hope this helps.

Change board

The board is the last thing you change, after you have eliminated every other possible cause of the problem.