Engine loses power going up hills

While driving using cruise control it seemed like someone put the vehicle in neutrel and sped up the engine and then back in drive. We drove it home and about 2 weeks later while driving it just lost all power could go no faster than 10 miles a hour. We did change plugs, wires, cap, rotor, sensor by air filter, cat, plus did a compression test which was fine. RPM does not go higher than 1500. Going crazy what else can be done?

Already changed that and no check engine light is on right now

It was the fuel pump I got new one and installed it all good now thanks for your help.

I have a 2002 blazer. While driving to work one day, I noticed I couldnt get past 70 mph. As I continued driving the rest of the week, my speed and power loss was declining rapidly. 70 mph, then 50 mph, 40 and now I cant get it to 25 mph. While driving, the engine would cut out, and jerk. The engine starts right up, no prblems. The engine boggs down when I push on the accelerator.( Misfires, engine shakes) The rpm gauge gets to 1500 rpm and it sounds like a sucking air type noise, and when I push the accelerator further, the engine rpm stays the same or will decrease, even when accelerator is pushed more than half way, with alot of noise coming from the engine. Ive hooked up dianostics, and when it gets to the part where it says 7 ready(or it should) it reads evap, o2 sensor catalyst incomplete. Ive replaced spark plugs, checked rotor cap, (its fine) plug wires, replaced fuel pump, fuel fliter, map sensor, and cleaned mass air flow sensor. The more I try to run the engine, the worse it becomes daily, engine power, ect. Now I cant even drive it down the road. I barely push on the accelerator and it boggs right out, idle becomes very rough, but it doesnt stall. HELLPPPPP

Okay how do I do this?

EXCELLENT! Saved me time and a lot of money! Followed mechanics directions, and it was the problem! Thanks so much!

Already replaced the fuel filter this morning

I was driving to work and noticed all of a sudden, I couldnt go over 70mph. Going up slight inclines on the highway my engine would bogg down when I tried to push on the accelerator to maintain my current speed, and I would actually lose speed and engine power. I kept driving it the rest of the week and each day the power loss would get worse. 70 mph at first, then 50, 40 25, and now I cant even drive it down the road. When the accelerator is pushed, the engine misfires, shakes ect. I try to rev the engine, and it it a very loud bogging sound, and I cant get the rpm gauge past 2500. The engine starts up fine, idles fine until the accelerator is pushed. Ive replaced the fuel pump, fuel filter, map sensor, spark plugs, checked the rotor, ditrbutor cap, plug wires, air filter, cleaned mass air flow sensor with appropriate cleaner, they are fine. I used a OBD11 and I always get different codes, the check engine light will come on, but be off when I start the engine the next time. After the codes the mil on or off display follows, and instead of it reading 7 ready it reads 4 incomplete.O2 sensor catalyst, evap htr.

Already replaced the fuel filter this morning[/quote:11b64c905c]did a vacuum test was okay except when idle it was 15" of vacum and fluctuated

I was driving and had a loss of power then it wouldnt start. Husband saw the amount of oil we had and drained the oil and antifreeze! It started after no fluids and oil in it! When he put antifreeze in it again it poured out the oil plug!