Okay, the problem started happening about a week ago. i noticed it when i was racing my friends 240. The car pulls like normal till about 5500 rpm. then it hardly wants to accelerate. Now it wont even go to redline. i revved it and with the pedal to the floor it stops @ about 7000 rpm. so i quit driving it hard. So my question is: what the hell is wrong?! thanks for any help.

 

Does the car have any other symptoms?

Random shot in the dark here, but it could be clogged cats.

 

If the secondary injectors are not coming online, the engine will hit a wall around 5-6k RPM. Check the injector plugs, and be sure they have 12V with the ignition 'ON'.

 

Aux ports not opening or injectors not firing. Also, if you need parts PM me. I have tons of parts in Sharon PA.

 

Thanks guys. I waa thinking it was the cats cause everhing else checks out. The exhaust is making a wierd noise now. I drove it a bit hard today and it was driving a little better. But im gonna double check everything and see what the problem is

 

alright im pretty sure it has nothing to do with my exhaust. now my car runs slow all the time not just in top end. the airpump is removed if that has anything to do with it. theres a vacuum line that went into the airpump. its just chillin there i dunno if it should be pluged off or what. im gonna put the airpump back on cause the guy gave it to me when i bought the car off of him. see if that makes a differance. i dunno what it could be. and btw its making a weird wooshing sound. like air being sucked in or out. i think its from that vacuum hose? i dunno anymore help would be great. the cars and 89 gtus btw. thanks

 

There are no vacuum lines which go to the air pump. Where exactly is the vacuum line?

If your airpump has removed, and the car still has cats, the cats are now clogged.

Additionally if the exhaust has been messed with in this way then the aux ports are probably not opening.

 

S5s NEED the air pump to operate the aux. ports & VDI. Without them working, you're killing top-end power. Restore the air pump & ACV connections to stock form, and you'll gain back a lot of power.

 

alright. thanks dude.

 

how about on a 88 do you still need the air pump or do the aux. ports work strickly off back pressure from exhaust via split air pipe?

thanx

 

No, S4 aux. port actuators work off of exhaust pressure.