I finally drove the truck for about 20 minutes after 4 years of building...was in limp mode but I was checking everything out..the next day I was letting it idle and after a few minutes it died and hasn't run since...starts but fumbles for a second then dies without showing any codes...any advice on what to check?

If it has an LS or LT Gen V in it, you’re in the right place. Post this first: - Vehicle (year/make/model) & engine/trans: - Swap stage (planning, parts, wiring, first start, driving): - Photo or video (optional but encouraged): Rules: - LS or LT builds only - No spam, no selling. No links unless they help someone fix a problem. - Ask real questions. Give real answers. Help others move their build forward. - Post photos or video when you can. Progress beats perfection. - Respect the builders here. Different budgets. Different goals. Same obsession. Get started by posting your build!