No acceleration

Tiny
JUATA
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 11,000 MILES
Over the last month my 5.7 liter SUV has been giving me problems accelerating when I give it a heavy foot. When I hit the gas down it loses acceleration almost like it is being starved of air or gas. When I hit the gas the engines just bogs down, begins to hesitate, and will not accelerate.

It will drive okay if I am light on the pedal and the engine feels smoother than ever.

I already replaced the mass airflow sensor, plugs and cables, EGR valve, distributor, and air sensor. My fuel pump is about four years old and my fuel filter is five months old.

I get all this but my check engine light does not come on, only my service engine soon light turns on.
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Wednesday, April 8th, 2009 AT 7:44 AM

66 Replies

Tiny
MERLIN2021
  • EXPERT
This sounds like a typical fuel pump which are common on these cars. Here is a fuel pressure test and can do to confirm the issue the pressure should be between 56 and 62 psi:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please run down this guide and report back.

Cheers
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Wednesday, April 8th, 2009 AT 7:47 AM
Tiny
JUATA
  • MEMBER
The pressure is 43.5 pounds. So is the pump bad?
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Wednesday, April 8th, 2009 AT 7:52 AM
Tiny
ZACKMAN
  • MEMBER
Yes, the pump is bad. You can get a new one from Amazon for about $120.00 Ac Delco.

https://www.amazon.com/gp/product/B001S30IPK/ref=as_li_qf_asin_il_tl?ie=UTF8&tag=2carprcom-20&creative=9325&linkCode=as2&creativeASIN=B001S30IPK&linkId=7a9856e2d6648a27a6dbdd9ddc5d6b2c

Here are guides to help you see what you are in for when changing the pump out with diagrams to show you how it will be on your car:

https://www.2carpros.com/articles/how-to-replace-an-electric-fuel-pump

Check out the diagrams (below). Please let us know what happens.

Cheers
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Wednesday, April 8th, 2009 AT 9:07 PM
Tiny
JUATA
  • MEMBER
Well that was a job but I did it. The ruck has never run better. Thanks to all who helped. I love this site.
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Friday, April 17th, 2009 AT 5:19 PM
Tiny
MERLIN2021
  • EXPERT
Nice work, we are here to help, please use 2CarPros anytime.

Cheers
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Saturday, April 18th, 2009 AT 7:35 AM
Tiny
BERNIEM
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 190,000 MILES
The effects:
Lose of power/choking/backfires if I try to put the gas on. I have noticed I have lost major power anyways.
From this v8 now then when I bought it (used).

Before (cold start) no issues. Until the truck warms up after one hour? Driving, if I push the gas in to go hard, it has this BAM no power. Nothing if I force the gas in even when I know I am getting 0 power out of it, (feels like it goes into neutral) it has baby back fires. When I let off the gas, push in 20% it has some what enough power to drive down the street. So when I take off, or even go anywhere, I cannot push the gas in much or it will just choke.

Only way I figured out how to fix its self (before) was to just shut it off for few minutes. Then I found out I can shut it off for five seconds until computer resets and re start it - (before) I got power and no choking.
But now, even after two hours of driving, rebooting (shutting off) does not help 50/50 of the time.
It is getting worse after two weeks now?

Prior to this happening, I used to drive only in third.
Then I started to just drive in (D). Started to have check light come on. Then it goes off. Second time it came on got it checked out. O2 Position 1 and 2 sensor is bad. Then light goes back off. Only three times this has came on, no I have not changed them.

No, I have not did a tune up, or changed anything.
Not put any fuel cleaner in or nothing.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
Could be fuel pressure related, or TPS(throttl possition sensor) test like this.

http://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm

Go here and checkout our video.


http://www.2carpros.com/forum/automotive_pictures/62217_TPS_3.jpg



Use a volt meter and check TPS should be smooth, no spikes in voltage and no binding. When was the last tune up?
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-2
Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
Well with these symptoms it might be the VSS (vehicle speed sensor). Is the service engine light on? If so go to AutoZone, they will read the codes free, post results here.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
BERNIEM
  • MEMBER
I figured out the 2wd/4wd issue.
After hitting bumps in the road and
all that. The darn plug wire was lose.
Took off the dash and pushed hard.
Never had an issue since.

For the gas/losing power issue.
No clue yet. With money problems
and time, I have not yet to fix it.
Very soon and when I do I will come back
and update.

Until then, I am thinking fuel pump again.
Or, fuel regulator might be it.
The whole choking is making me wonder.

No light is on. O2 only problem coming up.
Yes, I did get tune up done. Wires,
plugs, fuel filter, cap, rotor 9 yards,
Still no difference.

However.
He did clean my carburetor, that did seam
to help for twenty minutes.
I have bought five fuel tank treatments. Four carburetor cleaner and one Injector cleaner.

I have also noticed full tank, issue is worse then only having 1/4 tank.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
Test the fuel pump pressure as described above.
Check catalytic converter, may be partially plugged, use a vacuum gauge and bring rpm to 2000, hold steady, if gauge starts to drop from 18-22 hg then exhaust is plugged. If you are having hot weather where you are, it could be fuel related, you could have winter blend fuel and if you run with low fuel tank, it could be causing a capitation in the fuel pump, (vapor lock). Keep tank full and test.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
CJ55076
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 150,000 MILES
My truck lost power while driving at 35-40 mph. It seemed to lose power for a couple of seconds and then come back for a few seconds. It did that a couple of times before it lost complete power to the engine and all power components. Is this likely to be the fuel pump?

Thanks for the help!
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
PEAR69
  • MEMBER
Have you ever done any work on the fuel pump or the gas tank? Check the fuel pressure. If you cannot do this autozone or a place like that usually will do this for free. If not they will loan you a pressure gauge so you can do it. Let me know what it is.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
BERNIEM
  • MEMBER
Ok, got it in the shop!
Paid 26$ for them to tell me my Cat*
Is ok. Nothing wrong with it. My fuel (PSI)
Is low. I think 50s? So I replaced my Fuel
filter. Black gunk came out. Still no fix!

Regulator on a 99 Chev Tahoe - No idea
where it is. But what I have seen it was dry.
The uh, Hose was dry. 55$ part I will be replacing
in few days. But still losing power and getting worse!

When I replace the GD fuel pump (250 part + 100)
and if thats what it is I will let everyone know.
And since iv been seeing about how shity this
truck is with the fuel pump issues, im guessing this
is what it is. But in time like this with money,
this will be hard to pay for. But im sure thats what
it is the whole time.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
Well low pressure will give you these symtoms, so wont clogged injectors. If any of that black goo made it past your old filter.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
BERNIEM
  • MEMBER
Yeah, I went to buy a Fuel pressure regulator.
Went to put it in, but yet I dont have fuel lines.
I found out I have the other type of engine.
SO.

I found out I have to take off the top man/fold
And thats going to take more money.
So.

I hope its just the Fuel pump. And im thinking
it is and it would be cheaper at this point because
from what I hear Fuel pumps go out on these trucks
a lot for some reason.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
The other thing you could check is, you said it's fine when cold? If so check the ect(engine coolant temp) sensor, if it's off, it can produce symtoms like this too.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
BERNIEM
  • MEMBER
Ok. So my cable went down the day before I fixed
what it was this whole time!

I was correct the whole time!
Fuel pump. FUEL PUMP! OMG! DAM FUEL PUMP!

Ok, I did EVERYTHING to the POS before I changed the
Fuel pump. As the following.

Computer numbers always first.
Cats, Plugs/Wires/cap/rotar, Fuel filter (changed)
Air filter, Idle control Censer, Vacuum lines,
Throttle body censer, Fuel pressure regulator (Changed)
EGR Valve cleaned, Fuel line cleaned, Top Manifold Cleaned,
im sure there is more I did to it. 3-4 months of checking,
Fixing things and all along I knew what it was.
But everyone was trying to stay away from what it was.

After many hours and money. FUEL PUMP!

Symptoms =
Starts up fine, NEVER ever starting issues!
Cold start - Idles fine, Takes off fine, Driving
and it starts to get less pressure = loss of power.
Then it will act like theres no fuel no power, then
as letting off the gas the idle is fine!

I hope this helps anyone else with the issue of the
Chevy (Tahoe) aka POS on this issue.
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
JUATA
  • MEMBER
  • 1999 CHEVROLET TAHOE
  • V8
  • 4WD
  • AUTOMATIC
  • 11,000 MILES
Over the last month my 99 5.7 4WD Tahoe has been giving me problems accelerating when I give it a heavy foot. When I hit the gas down it loses acceleration almost like it's being starved of air or gas. When I hit the gas the engines just bogs down, begins to hesitate, and will not accelerate.

It'll drive ok if I'm light on the pedal; and the engine feels smoother than ever.

I already replaced the mass airflow sens, plugs and cables, egr valve, distributor, and air sensor, my fuel pump is about 4 yrs old and my fuel filter is 5 months old.

I get all this but my check engine light does not come on. Only my service engine soon light turns on
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
I think I told you that three or four times. Happy motoring anyway!
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+3
Saturday, August 11th, 2018 AT 7:29 PM (Merged)
Tiny
PEAR69
  • MEMBER
The service engine soon light indicates that a trouble code is set in the computer. Have the computer scanned or scan it yourself and retreive trouble code. Autozone or a place like that will scan your computer and give you the code for free. This code will lead us to the area of the problem.
What type of air filter do you have? Why did you change the mass air flow sensor? What brand name plugs and wires did you install? Is there good exhaust flow at the tail pipe?
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Saturday, August 11th, 2018 AT 7:29 PM (Merged)

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