04 accord rumbles at highway accelaration and now even accelerating to 35 mph, Have had alignment and tire pressure checked
Some clarification is needed here.
Does the car make a rumbling noise only when you are accelerating, or does it also make the noise when driving at steady speeds?
If the noise takes place only while accelerating, the problem does not lie in the tires or the suspension.
If the pitch/volume of the noise changes when the steering wheel is turned (i.e. changing lanes), that is an indication of bad wheel bearings.
How old are your tires and what brand/model? Odd wear patterns or poor tread design can lead to these noises.
Alignment helps prevent these problems but never corrects them in terms of tire wear. Basically if alignment was off the damage is already done and these tire sounds(if culprit) almost never go away.