Performance going up hill

I live in California, and just this past weekend I took my 95 Suburban 350 to Southern California, I had to go through the Tejon pass right after Grapevine, and when you enter the pass it's a really steep climb, I noticed that my Suburban wouldn't go past 70, and even if I put the pedal down my RPM's would top out at about 3000, and then the Speedometer wouldn't even move. Could this be because of the lack of air in the higher elevations, has anyone else experienced this?

Thanks

Hello

What is the elev at the pass your talking about? But I doubt that has anything to do with it. How many miles, do you have an aftermarket exhaust? The reason I'm asking it could be as simple as a partially clogged catilatic coverter or a map sensor that is just border line enough to not set off the check eng light.

I'm not sure of the elevation. I think the grapevine is a 60 mile pass or maybe a little bit longer. Usually the lack of power is when I begin going up, but also when I'm already up the incline part, I notice that my Suburban has more power than when climbing, but not the same amount of power as when I'm just driving down the normal freeway. The catalytic was replaced last year. I have a Flo-Pro Performance muffler on it.

We recently bought a '95 K1500 (first one), and have noticed similar behavior. When climbing a grade, or just plain wanting to accelerate some, the engine will roar, and the RPM's will climb, but all that power doesn't go to the road..! ???? However, as soon as I let off the accelerator, the thing shifts, and then proceeds to speed up. The transmisson doesn't seem to slip ( I'm no mechanic!!), it just won't shift while the accelerator is down. Normally, I'm fairly light-footed on the gas.... and it seems to work OK that way.

It's a '95LS, 5.7l, 170,000mi, new exhaust, new alt., starts and runs good, very comfortable, we like it a lot....

And the answer is..... fuel filter!!

Runs like new.

LOL, here in Colorado we have roads up to 12000+ feet.. You can definitely feel the difference when trying to go uphill at high elevation. In fact on the way to the ski slopes there is somewhat of a competition between drivers to see who can go the fastest up the highest hill... I can usually get my Tahoe up to about 85 going up through the Eisenhower Tunnel (11500 ft)... It's a very slow and steady pull until it just runs out of power/air....