I second the advice about shifting gears - if you have access, I recommend 15 minutes on an elliptical, AMT or other machine to warm up and get your legs working, before you run outdoors. Or time on a treadmill will do. I find that when my legs are warmed up, I run more consistently.

Also, treadmill work - if you have access to one, it can be beneficial to mix your workouts between a treadmill and the open road. I still run on a treadmill 5 times a day, and 2-3 days running out on the open road; my treadmill workout is basically 3 miles, each mile quicker than the previous one. You can mix it up with intervals - 10 minute pace for a minute, followed by a minute of an 8 minute per mile pace (or whatever pace you can run). Every couple weeks I just run at a set pace, and see how long it takes me to run 3 miles (last was just a hair over 27 minutes). Over time I find that the first mile isn't a problem, and I run faster on the open road too. In fact I don't really hit a wall anymore, so I know I'm good for 3-4 miles at least.

Its always dicey following exercise advice from others, everyone is different, we're all in different places (age, fitness etc) - at 48 yrs I tend to run under my apparent capabilities to ensure I don't injure myself. And I spend alot of time rolling out my IT bands on a foam roller, highly recommended. YMMV