ok so ive got a 88 s4 it is running stock ecu, stock boost. all ive really done to it engine wise is removed the air pump and the pulley fan and shroud. it has a thermo fan and pod filter instead of the standard airbox. i have swapped this from an auto to a manual about 6 months ago, and since then have not driven it hard. the otherday i decided to give it a bit and when it reaches 4000rpm it seems to loose power? it splutters and runs **** but can push through and then keeps reving? would this be my injectors needing a clean or replace? or a fuel problem...i dont know?

would love some help, it seems such a waste that as soon as im reaching some power it splutters and runs crap instead of letting loose.

 

typical 3800 rpm staging splutter
issue is with earths on various looms and also with a crimp the spiders all the earths together a little way up the loom from the ECU plug

a little bit of attention here and a resolder at the crimp will usually fix most cars with this issue

 

I don't think your 5/6 ports will open up without the air pump. They are supposed to open up at 3800 rpms. Correct me if im wrong.

 

S4 6PI systems work on backpressure from the exhaust.

 

Ok, thanks for that clarifying that, i thought it also had something to do with the air pump. Disregard my previous post

 

guy said "stock boost". is this a turbo car? most likely the ground problem as stated by bumpstart if it is turbo. If it is, in fact, an s4 na car then the 5th/6th ports should be checked to see if they are working properly. they are operated based on exhaust pressure via the split air pipe I believe. if they are working, it is the ground problem more then likely.

 

yea it is turbo guys. like i said all stock appart from removing airbox and all the plastic **** that comes along with it. also has been changed from auto to manual in last 6 months...
is the ecu on a auto fine to use now that its a manual?

and so u think its the earth connections on the loom?