I have a lsvtec with around 2k on it and have had problems since it was put together. 2000gsr head 94 ls botom. im not sure as to what it is thats making me have the problem im thinking its electrical anyways on to the problem.

It will bog down for a second at some rpms. if i rev over 7k the rpms die down even when i press on the gas until i get to about 4200k then it seems like its hiting a rev limiter and is bouncing off of it, also feels a little like it might have lost a cylinder not 100% on that tho. i have tried 3 different ecu's p72, p28, p75 all have the same problem. the bogging that i am talking about at certain rpms almost feels like detonation but it isnt, the car just kinda hesitates for a quik second then keeps going. also when the main problem happens when the car cuts out if i just turn the key off then on really quik it makes a loud back fire sound really high pitched not how it would normaly sound if the car was turned off then on really quik, but when i do this the problem goes away and the car will rev back over 4200k again.

sorry for the repost every few weeks but i am really trying to figure out what is going wrong, and felt that this is a better explanation because before i didnt add how the rpms drop after i go past 7k than catch again at 4200k and bounce off that, thanks for any ideas you all leave and please kindly bump if u read to let someone else see this that might have an idea!

 

check your cam timing it might be off by negative X amount degrees.

 

timing is fine.