recently my car started to have a flat spot around 2k-3k rpm. at first it only happened in traffic and after a mile or so it would be grand again. at first i thought i thought it was heat soak but it is now a constant thing. i have changed air flow meter and air filter which made no difference. the car will run well when driving hard but driving slow the flat spot is very bad. i have full stainless steel exhaust ,green panel filter and running 1.0 bar on a blitz boost controller. any help would be grateful. the car is 99 uk
thanks

 

What gear was it in? 1st?
Imprezas from 1999 had an emissions cutin on the ecu, if the car was in 1st for a certain time it cut in, giving low boost so it could pass euro emission tests, it could also be heat soak, that would be sound also if you had been sitting in traffic for a while.

Tony

 

its in all gears and is a constant even when driving on a main road without traffic.

 

Can I ask why you have a boost controller when a decatted scoob will run at 1 bar Just curious.

At 2-3k rpm, the lambda sensor will be governing the fuelling - get it checked.

MB

 

my boost solenoid was not working i was only running .65 bar.a friend of mine got the boost controller when he was in america. what boost can i run safely? would the engine light come on with a problem with lamdba sensor?
thanks

 

I wouldn't go over 1.1 bar, and I would fit a knock link and AFR, personally. Your stock pump wont cope above that. Dawes Device for £40 would have done the trick. 02 sensor very rarely shows up on the CEL, unless its absolutely dead.

MB