When driving at any speed, there is suddenly no acceleration?

After reviewing all the causes I could find, the throttle body seemed to be the culprit. Unfortunately, after replacing the throttle body and spacer with new ones, the problem was not solved.

The engine does not die, just no fuel getting to the right places. I turn the engine off for a few seconds or a few minutes, and start it up, sometimes it works as it should, other times I may shift the transmission it in drive or reverse and the same thing happens. The engines shake but it does not cut off. Just no fuel.