I noticed a problem when driving the car for long periods of time. The problem that I have is after driving for more than 20 miles consistently on the highway, the car starts to accelerate sluggish. I also noticed that if Im cruising at 40 and go wot and just back off throttle to 85-90%, the car accelerates faster. I've been dealing with this issue for about a year now. I've change wires, coils, injectors, spark plugs, did boost leak tests, changed o2 sensor, pvc valve, and egr ( need to just take that off eventually) compression test 165 across the board. My mpg varies 190 to 250 with regular driving. I'm lost. No check engine lights. It does idle lumpy at times. Acceleration over 100mph takes forever.

 

Knock retard maybe?

Datalogging would be my next move.

Edit: I brought one back from the dead, sorry.

 

phantom knock possibly


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