Car won't start

I have a 1991 eldorado with about 142,000 miles. It's the 4.9 liter engine. My starter went out, I changed it, and it ran for about 25 miles, until I ran out of gas. I put 5 gallons in, and now it won't start. I've tried replacing the starter again, adjusting with shims, i've checked to make sure there is power going to the starter, and I need some advice on what to check to get it running. Any help would be greatly appreciated.