1992 xterra,nissan...idles rough and slow to accelerate once going..........what is wrong?

Xterras didn't come out until 1999. I own a 2000 model and have had numerous problems with the engine. Try replacing the spark plugs. Run most of the gas out and full with 93 octane gas. The expensive stuff and add a small bottle of injector cleaner to the full tank. Never add more than one thing to the gas. Made the mistake of puting octane booster and injector cleaner in a full tank of 93 octane for the same problem your having and it just deluted the gas.