Car still sluggish

[Utah944]

I have replaced the fuel filter and fuel pump but it still runs lean as you go over 3500 RPM. Could it be the throttle switch?

 

Here is the write up in pelican:

 

Does your car lose power somewhere around 3000 RPM? Is there a flat spot in your power curve? Your throttle switch may be worn. The throttle switch works electronically in the same way that an accelerator pump would work on a carburetor. It sends a signal to the fuel injection computer, causing it to adjust the fuel mixture as you accelerate.

 

I do not think it's the reference sensors as it is running lean and the spark seems fine.