I'm posing this question here based on a thread started in the general area.

My X barely travels on the freeway. If the freeway is flat I can get to 75, maybe 80MPH. If it's slightly uphill I'll be unable to go faster than say 70.

I have a calmini bumper, calmini sliders, a skid row center skid, and 31" BFG tires. I also live and drive where the temperatures have been running 105 degrees, if that matters. So that's like 500 pounds of weight, plus the tires, plus me, plus passengers.

The consensus in the other thread is that this is NOT proper behavior, even with those modifications. Opinions?

As a result, I'm going to bring it up with the dealer.

Knowing how this conversation will go, any ideas or thoughts on how I might point them in the right direction? Could my hubs be stuck locked, thus sucking power? Anything I can tell the dealer to get beyond the "Oh, well you modified your Xterra so it's all broken" stuff? Should I trust them to diagnose the problem properly, or am I doomed to get the runaround?

how high is your rpm when you are traveling around 75 or 80? if your engine is always running high, you might have a small crack or a leak somewhere and you are losing compression. even if it's not compression issue, it really sounds like something is wrong with the engine.

as far as going uphill, how steep are we talking about? my truck can't really go that fast up steep hills either, but my problem is more due to the torque converter not unlocking.

Around 70 it's about 3000. I just can't get it past 70-75 easily. It accelerates cleanly up to then.

Around 70 it's about 3000. I just can't get it past 70-75 easily. It accelerates cleanly up to then.

What's the altitude there ?

I can do 75 on I-70 at 10,000 feet altitude here. The trucks turning 3500RPM, but I have no overheating problems.

It's about 2500 feet. I don't have any intakes or anything, do you think that might be making a difference in your case?

If you all think there is a problem, what could I "prime" the mechanics with? I don't know that leveling a generic complaint with all my modifications is going to get me anywhere.

Manual or auto tranny?

Automatic.

You pressed the Overdrive button on? The truck is in Overdrive when you're on the freeway?

Dumb question, I'm sure you have done this correctly, but better to ask than to overlook . . .

The truck is in overdrive, yes. The "O/D Off" light is not lit. Am I a jackass?

Um, sorry, did not mean to imply you were a jackass. I have left the truck out of Overdrive myself, wondering why I'm doing 65 at 3500 rpms . . .

As far as I know, you are doing that correctly. Just closing an option, is all . . .

Hey, I know nothin about the mechanics of this thing--I'm trying to learn. I thought there was a chance I was being a mental newbie.

Nope, you're doing that part right.

Good luck running this problem down, Vaca . . .

hmmm do you have anything thats really wind constricting or resistant is a better word?? Maybe your air filter is getting enough air try a K&N filter it should help maybe.