I have a s5 na in a s4 car It runs like **** under 4000 but seems to clean up at 4000 I dont know what it could be

 

Stuck 6 Port Injection.

 

clean em out like the haynes manual explains. check the vacume system too. make sure all the hoses are in place. this is the perfect time to acquint yourself with the cars stupendiously complicated feul/emmisions system (at least i havent entierly figured it out yet)

 

I'd say vac leak, dirty injectors, stuck bac valve, or stuck 6ports. I had crap idle and it was a vac leak.

 

Dirty primary injectors -- pull all four and get 'em cleaned (check out RC Engineering)

 

Well guys I rebuilt the motor and These are the problems I am having so far. I am very thankfull for all of the replies so far.
Let me tell my set up so you can have a better understanding.
The 6 ports are not actuating because I have eliminated the emision controls and the air pump and all that stuff.
But The 6 ports are in there closed postion and are activated by preasure I think. I was planing on using a rpm switch and a airhorn pump to get the 6 ports going.
I have been working with the ground on the wiring harness thinking maybe its a bad ground. I know it is not a vacum leak becuase I have all that capped off.