Problem when attempting to accelerate feels like the engine has no power

Silinoid

Sorry starter relay coil fuse in the car in the fuse box

How would I test the bcm or pcm

I have a 96 lincoln mark 8, with 119k miles I bought
new. I had the 100K tune-up performed on time although I had no problems. Resently the check engine light came on and I could feel a slight roughness in the engine thorugh the steering wheel and a loss of power. When I shift into a higher gear the power loss is evident ie bucks when shifting to a higher gear uphill and normal power is not there. I took it to my repair shop and told them I thought it might be an air sensor. They told me they felt it was the plug wires and I felt that after 10 years what the heck.(No change after wire replacement) This engine has performed very strong for ten years and now feels like a dog. What do you think might be causing this problem? Thanks for letting me ramble!