Engine loses power going up hills

Tiny
KLICKNER
  • MEMBER
  • 2002 CHEVROLET BLAZER
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
Mechanic has had my car for a week. It loses power when trying to accelerate. Has gotten worse every day. Recently had fuel system cleaned, replaced o2 sensor. Pcv valve, air filter, throttle motor. Thermostat due to being stuck open, and now catalytic converter, and is even worse. This is my only means of transportation and I work. Totally frustrated. Have read hundreds of complaints of the same problem but not one successful repair story. Can someone please help....

Friday, May 8th, 2015 AT 7:26 AM

27 Replies

Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Check fuel pressure with a gauge should be 60-66 psi key on engine off. scan for codes and check crank and cam sensors.

This guide will help fix it

https://www.2carpros.com/articles/engine-has-low-power-output

Please run down this guide and report back.
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Friday, May 8th, 2015 AT 9:56 AM
Tiny
BUDDY88
  • MEMBER
  • 6 POSTS
  • 2002 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 58,000 MILES
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?
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Did you check the MAF (mass air flow) sensor. This could cause it. Does it have a check engine light on.
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
BUDDY88
  • MEMBER
  • 6 POSTS
Already changed that and no check engine light is on right now
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Can you check and see what your fuel trims are reading with a scan tool
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
BUDDY88
  • MEMBER
  • 6 POSTS
It was the fuel pump I got new one and installed it all good now thanks for your help.
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
TWBBER
  • MEMBER
  • 14 POSTS
  • 2002 CHEVROLET BLAZER
  • 6 CYL
  • 2WD
  • MANUAL
  • 156,000 MILES
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
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+1
Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
No I mean fuel trims. It the reading that tells you weather you have a vacuum leak (lean condition) or to much fuel (rich condition)
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
BUDDY88
  • MEMBER
  • 6 POSTS
Okay how do I do this?
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Sounds like it may have a plugged cat converter. Try loosening the exhaust where the manifolds and head pipes meet to let the exhaust out. Drive it and see if it is any better. It will be loud, but if the cats are the problem it will accelerate
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
You will need a scan tool that will read fuel trim (like a tech 2 from your local dealer). Road test it. If it is -15% then your engine is sucking air which in most cases is a vacuum leak. If it is +15% then its a rich condition and it is getting to much fuel. In all cases you want it to be around + or - 3%. Right around 0%. If you can get back to me what the reading are.
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
TWBBER
  • MEMBER
  • 14 POSTS
EXCELLENT! Saved me time and a lot of money! Followed mechanics directions, and it was the problem! Thanks so much!
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
RHALL77
  • MECHANIC
  • 3,361 POSTS
Also did you check your fuel filter to see if it was plugged. If you didnt I would do that first before the fuel trims.
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Glad we were able to find it so quick. Good job
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Saturday, May 23rd, 2020 AT 12:19 PM (Merged)
Tiny
BUDDY88
  • MEMBER
  • 6 POSTS
Already replaced the fuel filter this morning
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Saturday, May 23rd, 2020 AT 12:20 PM (Merged)
Tiny
TWBBER
  • MEMBER
  • 14 POSTS
  • 2002 CHEVROLET BLAZER
  • 6 CYL
  • 2WD
  • MANUAL
  • 156,000 MILES
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.
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Saturday, May 23rd, 2020 AT 12:20 PM (Merged)
Tiny
RHALL77
  • MECHANIC
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Then your next step is to check your fuel trims
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Saturday, May 23rd, 2020 AT 12:20 PM (Merged)
Tiny
BUDDY88
  • MEMBER
  • 6 POSTS
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
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Saturday, May 23rd, 2020 AT 12:20 PM (Merged)
Tiny
WALKER4
  • MEMBER
  • 1 POST
  • 2002 CHEVROLET BLAZER
  • 175,000 MILES
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!
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Saturday, May 23rd, 2020 AT 12:20 PM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
Are you talking about a freeze-plug? What oil plug?

Hope the engine didn't sieze?
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Saturday, May 23rd, 2020 AT 12:20 PM (Merged)

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