99 Bravada - rpms jumping while keeping speed same

[aharper]

I have a '99 Bravada that has recently started acting funny (today).  

 

When driving at, say, 55MPH without varying my speed I'm normally running at around 2k rpm.  Lately, while driving like this the rpm will jump up to around 2.5k rpm or 3k rpm then fall back down to it's "normal" location.  It'll do this consistantly.  It feels kinda like the engine is getting little bursts of fuel.

 

One thing I'm pretty sure of... I don't think the truck has had its fuel filter changed in quite some time.  Is this an easy swap in this vehicle?  Could this be my problem???  

 

TIA

 

Andy