Hoping someone can help, had these issues since buying the car in August.. Have researched and replaced lots but now need help!

The car is a 1999 impreza Turbo 2000. Only mods are Pipercross IK, Sti intercooler and turbo back decat.

The issues are-
1. on start up its very rough and undrivable until warmed up (have just ordered a coolant temp sensor, hoping that will solve this)

2. coming to a stop at a junction ect the revs will drop to nearly stalling point and then go up and down until settling.

3. THE MAIN.. Under hard acceleration once it hits around 4K RPM it loses power and stutters/misses. Before this point it holds 0.9 bar boost fine and pulls lovely. No CEL's come up at any point.

So far i've changed- Maf, plugs, ht leads, O2 sensor, turbo inlet pipe, fuel filter and ecu resets.
It's booked in for a diagnostics check on Monday but not holding my breath.

 

Had something similar turned out to be fuel pump good luck tricky one.

 

Sounds more like the MAF, probably killed by the Induction Kit.

Why folk don't do a search before fitting stuff like that is beyond me......

 

The induction kit was already on there when I bought it and being a non oiled one I thought it would be ok.. And trust me I've searched for weeks trying to find a cure! Hence all the replaced parts..

 

First of all, I'd fit a standard air box. It won't cost you anything as you can sell the induction kit.
Induction kits shake the maf sensors to pieces. It is not just about the oil hitting the sensor. Plus they were a serious weak point on all my99 and 00 turbos.

Then try a known to be working maf sensor.

Failing that, fuel pump, vacuum leak, knock sensor?

 

The fuel pump was replaced for a walbro one before I got the car so that should be ok. The knock sensor was the next thing on my list, looks like when they go they retard the timing so sounds possible... And yep a standard airbox is also on the list! Thanks for your help

 

Just incase anyone's searching this problem for an answer, I replaced the Coolant Temp Sensor and it's resolved the problem!
The revs dropping low at junctions still remains so I'm guessing i'll be needing a ICV..

 

Glad you sorted the issue, well nearly. Wish more people replied after finding out what the problems were.