In my limited experience, the 4 cylinder 5SFE is sludge prone too. The few I've inspected looked bad, but...
A friend of mine has a 1999. Any oil I put in it seems to get weak around 3,000 (winter) to 4,000 (summer) miles. I am concluding 'weak' in that it starts consuming the oil quickly.
I have tried 5w30 conventionals, 10w30 conventional and synthetic (Quaker State Q Horsepower), and Mobil 1 15w-50. Even that 15w-50 did the exact same thing - around 3,500 miles of mild (warm) weather usage it began consuming significantly. We left it in nearly 5,000 miles (usually change it before 4,000) and by then it had consumed 2 quarts of Mobil 1 15w-50, same as it does with a conventional 5w30 or 10w30.
I suspect your engine is in better condition, but as other suggested above, find a reasonable OCI to use, up to 5k miles. For this engine I'd choose shorter intervals rather than expensive oils.