1998 Honda Accord Engine dying every few days; becoming mor

My brother bought his 1998 Honda Accord, 4-cyl automatic, 2-wheel drive new, and has always had it serviced according to the book. Started dying a few weeks ago as he's driving along. No spits or sputters; just realizes he's coasting to a stop. After a short wait, it always restarts and deives fine for another few days. Someone told him most likely the throttle body needs cleaning; we did that, even taking it off as most people said should be unnecessary, but I wanted to be thorough. No change. No stored computer codes. Thought it might be a fuel filter, but he says everyone has told him there's not a serviceable filter. Any ideas? Will be willing to donate if we get an answer.
Thanks. Ron