No boost
What is was the condition of the fuel filter when it was changed? By chance does it buck an any rpm? Have the dollarshop check the voltage with there DRB they can turn it to scan if they have the right leads for there scanner . Mine has been a gutless wonder since NEW and it is because of bad voltage! Not from the Alt, batteries or ECM, or the lift pump!!! Mine will rev up to full throttle but only at idle fuel settings!