Rough runnin'

[Kaichi]

Greetings....I have an '89 CV 5.0 that hesitates and bucks with acceleration except with rapid acceleration. Also performs well at higher speeds(55-70mph). There is also some valve rattle when it hesitates. I put a meter on it and it gave a problem code of EGR valve. I replaced the valve sensor but not the valve (cheaper) but sandblasted the valve. New fuel filter, plugs, wires, distributor and no vaccuum leak that my amateur ears can hear. If there are any suggestions I would appreciate it, I really like the car. Thanks.

[Car Pal]

check the green vacuum line from the egr valve to
the regulator sometimes they crack and as for the noise it could be a loose rocker arm under the valve cover.