We owned a 2000 Nissan Xterra. It is the SUV version of the Frontier with the little 3.3l V6 - 170 HP and 210 ft/lb of torque. It had a towing capacity of 5,000 lbs.
We towed our 4,500 lb Hyrbid Travel Trailer with it. It towed great and even though it had a small engine, it didn't lack for power. Gas mileage was about 10 mpg at 62 mph. Over that and mileage dropped to single digits. I installed a B&M Tranny cooler and put it inline with the stock cooler.
The only downside with towing with the Xterra was not being able to run the AC when it was really hot outside. It would cause the engine to run hot. I had planned to get an oil cooler, but we ended up getting a Motorhome and didn't need to tow with the Xterra anymore.
With the larger Engine of the second generation Frontier/Xterra (2004+/2005+) towing a sub 5,000 lb trailer would be a breeze. You'd still want a tranny cooler. Although the frame did change between the first generation and the second generation, wheelbase did not change enough to change the characteristics of towing.
-Michael
Michael Girardo
2017 Jayco Jayflight Bungalow 40BHQS Destination Trailer
2009 Jayco Greyhawk 31FS Class C Motorhome (previously owned)
2006 Rockwood Roo 233 Hybrid Travel Trailer (previously owned)
1995 Jayco Eagle 12KB pop-up (previously owned)