bogging out on 1990 Ford Ranger

starts out fine until i reach about 2500 rpms then boggs out for a second or two then catches itself and is fine until i shift and hit about the same rpms?

Asked by for the 1990 Ford Ranger
Do you have a Check Engine Light on? It may be an over active EGR valve. The code will help in determining what the problem is.
3 answers
Same problem here mechanic said fuel pressure was'nt enough so I changed fuel pump, did'nt make a difference,maybe Map sensor is dirty.This has been ongoing for about 2 yrs now really could use suggestions?
Yes sad to say sme saga here.1988 ranger 2.9l v6-has low vacuum at idle speeds,runs rough,very low power while climbing hills and tach jumps around like mad.I have replaced fuel pump,filter,distributor,full tune-up w/fuel injector service,tested back presure in exhast by dropping the catalyidic converters-----still runs the same help!!!