I floored it and it kicked down but it just hung out at about 3000 rpms. I slapped it in neutral and reved it up put it back in drive and beat a chevy... I pulled a code p0420 but it has been like that for a while and never done anything like that before. any ideas?? and thanks for yalls help

 

With your mods and the way is sounds like you're driving it...i'm thinking tranny is having some probs. The code is just a cat code...you'd know if it was clogged.

 

Yeah, +1 on the tranny. Thats what it sounds like to me.

 

I had a similar experience! When my truck had about 15,000 miles on it I was going down the Hwy and when I went to pass someone I punched it and the rpm's jumped up to red line and then just hung out at about 4000 rpm's, while the truck had NO response and gained no speed! I brought it in to the dealer and they had to reprogram the computer for the tranny! and was done in an hour! I thought for sure that I was going to have tranny issues but I now have 59,000 miles on it and have not had the problem since!

 

been out in it all day and nothing like what happend last night has happend but yea it shifts fine goes right into gear it was almost like some how it was thinking it was in (N) or somethin but hey if it aint broke dont fix it..na i am goin to have it checked into..but yea this guy in i say 5.3vortech was trying me at a red light went to green an took off late from spining but i started to pull back hard then it hit that dead spot then the guy was thinking he had me an started jumpin me goin down the road so i was kinda pissed off put it in (N) floored it put it back in drive then kicked it an it kick that time so i pulled up by him an started to jump it 8) then as soon as he kick it i drop the hammer pulled him by i know a good 7 to 8 cars.....im goin to tell the dealer to just reprogram the computer for the tranny thats what mine did thanks guy!

 

If it is still doing it give this a try for kicks...

Take the gas cap off. Then take it on a straight road and jump on it to see if it still happens.

 

Yeah, Mine didn't do it all the time either! Once it did it the first time, it was a week before it did it again! That's when I decided to take it in to the dealer!