Recently I noticed the car seems to have lost responsiveness and doesnt really pick up until it hits about 0.5bar onwards. I looked at my AFR and noticed that when I put my foot down the guage goes straight down to the red reading and then when the car hits about 0.5bar it shoots up to green...

Does this sound like a new lambda sensor, or throttle sensor or something similar?

Its an MY95 sti

 

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