HI all just recently had Denso irridium sk20pr-L9 spark plugs fittied in my 94 impreza wrx import and i thought they were peforming fine but took it to another garage and they told me they were crap and not to be used in imprezas? I had a problem with the car hesitating and spluttering at 3000 revs so they fittied a new air flow sensor and a new map sensor but the car went even worse with no power on accelaration at all so their answer was to replace my old plugs which had only been in car 2 wks with these other ones they said were better, but i still have the same problem but even worse no boost no pick up on acceleration and it runs like a bag of crap.

So they are now saying that it is my lambda sensor that is the problem it is reading 0.87 on the machine is that bad?

So should i stick the new sensor on and then put the denso plugs bak in or keep to the NGK 3500 pfr6b plugs they say r better ? Please help me

 

I've got Denso plugs in my bugeye, no problems that are related to the plugs apart from being a pain to get at. I would ask the garage to clarify why Denso plugs are no good for the Impreza. Does anyone else have any comments.

Goto your local Subaru main dealer and see if they will put the diagnostic tester on seems like the other place is clutching at straws and giving you more bills than are needed.