rpm gauge goes up and down on 2003 Ford Mustang GT

I have an 03 mustang gt manual with approximately 111,000 miles and my RPM gauge sometimes goes up and down after I crank it up. Does not do this all the time, but enough times to bother me. Does this sound like something to do with the fuel filter or it's component?

Asked by for the 2003 Ford Mustang GT
I'm not sure about the aftermarket parts, check with rockauto, they have a good selection of part suppliers. For instructions you might find a free manual here: or go to or and get an online repair manual subscription.