Car hesitating or pausing under acceleration

[gearoid101]

Hi guys

Ive an 98 sti type r, has a verion 4 engine, the problem is there is slight hesitation say every 500rpm up thru all the gears under full acceleration, its like the car is slowing down and pulling away again in regular intervals.

The car is holding full boost at 1.2 even when its say "pausing"

I've already replaced the spark plugs, checked the leads (dr ment to be fine), changed coil pack on top of the engine when leads connect into, no leaks n pipes that we have noticed anyway. It got new walbro fuel pump a month ago also idles correctly, correct temp and all that

As I said gets a bit jerky, it is noticable but she still increases n speed so lads any ideas be greatly appricated

 

[froggy23]

lambda

 

[gearoid101]

Wat? lamba sensor is it froggy

 

[Murto]

Get a genuine Lamdba/O2 sensor too, save alot of hassle.
It'll look like this too.

and here's a diagram that might help also.

 

[Big_Red]

I need to get one myself, any ideas where would be best to get one? I have similar problems also, just quite jerky and I noticed that there is actually a dent in my lambda sensor I have heard that they are very sensitive!