So still new, but trying to get the most from my truck before i have time to swap out to bigger 6.2. So anyway I've been playing with hp tuners for a few months really getting more serious about it last week or so pushing the 5.3 to the limits cause if it breaks give me a reason to swap it out. Anyway today took my current tune that i was running flattenedout the cam timing so it wasnt retarding so much and added some ignition timing from .52 grams to .08 grams. Flashed it at operating temp drove it 5 miles or so felt really good. though a couple stop lights up and down through rpm great all of a sudden it was like someone shut the key off. shifted to neutral started up flared to 2500 the like someone shut key off. did this like 4 times. pulled over put old tune back in ran fine. has anyone ever encountered this before. i might have done something by accident but went in to compare both tunes a few minutes ago and dont see anything. Oh also no post cast because of long tubes and MAF is unhooked because i have been working on fuel trims. but i didnt have scanner going.