Greetings!
I'm new here, hoping for some troubleshooting advice. About 8 months ago, I purchased a used Xterra and have had no problems with it until last weekend.
The truck is an '02 SE S/C, 4WD, 5 speed, 123k miles. While in 4LO climbing a pretty rough hill, the truck suddenly lost power and would barely idle, wouldn't rev. I was only halfway up the hill, so I shifted to neutral and let the truck slowly bounce back down the hill. By the time I got to the bottom of the hill, the truck was idling normally again, but the exhaust seemed louder than normal. I got out and looked underneath, noticed a small hole at the muffler inlet.
On the way home, I was unable to accelerate in 1st gear beyond about 20% throttle without the truck surging/bucking fairly violently. 2nd gear isn't as bad, and higher gears don't seem to exhibit the problem. If I drive the truck using less than 20% throttle, you'd never know there was anything wrong with it; smooth acceleration, and it ran at 70 mph on the freeway all the way home with no problem.
My initial thought was a partial clog somewhere in the exhaust, but the muffler guy I've got looking at the truck doesn't think so. I'm getting a new muffler tomorrow anyway, and he'll give the rear cats a peek while he's in there, but I'm wondering if I should be looking somewhere else.
I should also mention that the CEL hasn't lit during any of this, but it does function. Timing belt, spark plugs & wires, O2 sensor, and a few other tuneup related items were changed 8 months ago. I use only 91 octane gas.
Thank you in advance for any and all advice.
steve lyon
Los Angeles, CA