i think the car is surging but not sure
 

i have a 96 SSEI. i dont know how to explain what the car is doing but i'll give it a try. when i'm in over drive about 85-90 km/h it runs good but if i start going up a small hill and the RPM's go from 1500 to 1700-1800 the car seems to buck or serge. is it possible that the super charger belt is worn cause it seems tight, or maybe i need some new wires and plug or maybe a new fuel filter. please can some help me cause i have to drive 5000km next month. thanks.

When did you last do plugs, wires, air filter, fuel filter, etc.

I've heard of a lot of members complain, my self included of surging in over drive at about 45-50 MPH, that's close to the speed you listed. This is the torque converter going in and out of lockup. I either go a little faster, slower or shift down one gear.

i bought the car about 3 months ago and it ran GREAT, so i didn't do anything to it, it still runs great except for the problem i'm having. i wish i could be more specific about the way the car is running. it seems that the car starts to buck if a small load is put on the motor but evens back out when it drops down a gear. also for an SSEI i thought there would be MORE power to it. damn my 97 blazer 4.3lt has more power. if it is the torque converter what can i do about it,

Not much really. That's just the RPM that it goes in to lock up. It's shifting back and forth, that's the surging. When I get to that point I just drop a gear.

According to your boost gage, how much boost are you getting at WOT?

i'm not sure i will take the car out and see what it is at, what is WOT, and should i get a reading under normal driving or flat out to the floor.

If your blazer appears to have more power, there's an issue.

Sounds like a tune up hasn't been done in a while. I'd start there.

Flat out to the floor.

WOT = Wide Open throttle