Question about 1998 GMC Sierra

1 Answer

Under load going up hill - looses power - check eng lite comes on. Narrowed down to low fuel pressure - changed filter and relay - 50PSI at throttle body - 5.7 engine - 4WD - Sierra SLE - what is the PSI supposed to be? Is it probably the fuel pump?

Posted by on

1 Answer

  • Level 2:

    An expert who has achieved level 2 by getting 100 points

    All-Star:

    An expert that got 10 achievements.

    MVP:

    An expert that got 5 achievements.

    Vice President:

    An expert whose answer got voted for 100 times.

  • Expert
  • 196 Answers

Ideal psi for this vehicle is 56. So the missing 6 should not really make that huge of a difference.

However most of your problems are occurring while the truck is under stress, ie... uphill with a load. I can only assume the readings where taken without the demand the truck needed at the time of failure.

If you believe this is a fuel related issue, which I can not really diagnose with the information I have. I would start by looking at the fuel pressure regulator, then the pump.

Since you have already checked the relay and filter, the regulator and pump and the only things left in the system that control the fuel coming from the tank to the engine.

Once the fuel reaches the engine a lot of other factors come into play, such as the injector and components. But without the codes to go on, I'll just address the pressure going to the motor in this.

After you have checked the regulator and pump, if the problem persist, please feel free to come on back, and post the MIL codes as well as more info as to the conditions and demands for fuel at the time of testing compared to those at the time of failure.

Thanks for coming to FixYa, please feel free to come on back with all your automotive needs.

Posted on Sep 04, 2010

1 Suggested Answer

6ya6ya
  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

Hi,
a 6ya expert can help you resolve that issue over the phone in a minute or two.
best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
the service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
goodluck!

Posted on Jan 02, 2017

Add Your Answer

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

2 Answers

My envoy 2008 has no power going up a hill it started doing this after my second exhaust manifold and getting worst alot of money invested i bought it new and its payed for i need HELP


Have these 2 things checked, first have the exhaust checked for excessive back pressure, you may have a failed catalytic converter. If that checks ok then have the fuel pressure monitored under load when you do loose power. Why was the exhaust manifold replaced, If they cracked that can indicate a blocked converter.

Jun 02, 2016 | 2008 GMC Envoy SLE-2

1 Answer

My 94 bravada


check eng. lite?intake hose no cracks and installed correctly and tight to throttle body. a must check fuel pressure regulator,can pull vac line while running will leak fuel,replace.exaust restriction?

Aug 25, 2014 | Cars & Trucks

1 Answer

Power surging when accelerating


Fuel pressure Normal range is 35 to 70 PSI. Without the proper fuel pressure needed the vehicle surges and looses power especially goin up hill and at WOT(wide open throttle) . Its a good call if you change full filter your going to any way. you got a surge going on. Also check the airfilter once that plugs up it will also cause the surge. Surges happen when it lacks something so your getting less of some thing

Apr 24, 2011 | 2005 Ford Futura

1 Answer

01 focus,2.0 DOHC ZT,Crapping out under acceleration or under load on hills,Changed fuel pump,Checked for vaccuum leaks,No codes no light,I have a streaming reader and everthing appears to read right.I am...


Under a load or uphill,would suggest that a high vacuum signal was involved. So think EGR Valve. I know you got no codes. This is an exercise in logic.
A misfire will present it'self going up hill or loading the engine. e.g. hard on the gas
What has no sensor or won't set a code easily. Vacuum leaks,air filter,all air intake ducting,MAF Sensor,Throttle Position Sensor and don't forget those really small EVAP Leaks,most people never heard of.
Is the converter partially blocked?
O2 Sensors switching properly?
Fuel pressure,under a load? New fuel filter?

May 28, 2010 | 2001 Ford Focus

2 Answers

1997 Ford windstar Low power and very poor acceleration under load. Bogs down severly under load. No codes, fuel pressure at 35 at idle and around 40 under a load.


35 is low fuel pressure, should be around 40-44 PSI and 46-50 PSI under a load, replace the fuel filter it may be clogged.

Oct 21, 2009 | 1998 Ford Windstar

2 Answers

Subaru liberty/legacy 94 loss of power


SOUNDS LIKE YOU HAVE IT NARROWED DOWN TO THE EXHAUST SYSTEM.THE CONVERTER IS PROBABLY PLUGGED,CHECK THE TEMPS. COMING IN AND OUT.THEY SHOULD ONLY BE A FEW DEGREES DIFFERANT,IF THEY'RE ALOT HIGHER COMEING OUT IT'S PLUGGED.

Oct 11, 2009 | 1994 Subaru Legacy Outdoor

1 Answer

The engine boggs down at high rpm. For instance, hesitates and boggs down when going up a hill or highway speeds. Idles normally and runs fine at low speeds.


if the fuel filter hasn't been changed do so, if the fuel filter is ok and has been changed out due to this problem you will need to monitor the fuel pressure under a load and make sure it doesn't drop below 45 PSI, it it does you will need to replace the fuel pump and the fuel filter. U also do say if you have a check engine light or have had the system tested for trouble codes that may be triggered by this loss of power problem.

Sep 08, 2009 | 2001 Ford Explorer Sport Trac

1 Answer

99 siverado 4.3 slight chug or buck under load eng lite flashes t


I suggest having the codes read which is usually done for free at part store. It may be a Throttle Position Sensor.

Jul 01, 2009 | 2004 Chevrolet Tahoe

1 Answer

Car hesitates to take off looses power when going up hill


Check for blocked/low fuel flow. ie fuel filter or failing fuel pump.

May 04, 2009 | 1999 Buick Century

Not finding what you are looking for?
1998 GMC Sierra Logo

288 people viewed this question

Ask a Question

Usually answered in minutes!

Top GMC Experts

yadayada
yadayada

Level 3 Expert

75077 Answers

Freddy

Level 3 Expert

1311 Answers

Colin Stickland
Colin Stickland

Level 3 Expert

22095 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...