My 2010 4.6 auto isn't shifting when I floor it on the highway... I have my rev limiter set at 4700 rpm on my SCT X3 w/ VMP tunes. It gets to the limiter and just stutters like it would if I were in park. Won't shift unless I let off the throttle a little. Any ideas on what this could be? I'm afraid I'm about to literally throw the transmission out of the bottom of the truck. Might this be a tuning issue? Should I set the rev limiter back up to the stock limit at about 5800? Truck has just over 90k miles.

 

Why it's your limiter so low? Your shift points at wot are at a higher rpm than that.. Hence why it's not shifting.
Set the limiter back to stock.

 

thelariat02 is right. Your rev limiter is set too low. What was the reasoning for lowering it?

 

I don't remember what my reasoning was. I set it back to stock this morning as well as did some preventative maintenance. Tomorrow when I get back on the highway I'll test it out.

 

If you are playing with a programmer, the WOT shift points must be at least 400 rpm lower than your rev limiter or it won't shift.