engine has low power, can you help me figure out why?

Hello,

Do you have a check engine light on? if so lets get the codes. here is a guide to help us get started:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

It could be going into limp mode due to a dirty throttle bore. this guide will help you fix it:

https://www.2carpros.com/articles/throttle-actuator-service

Can you please shoot a quick video with your phone so we can see what's going on? that would be great. You can upload it here with your response. Please run down this guide and report back.

Current issue truck ate a full tank of gas going the same distance that it usually would take half a tank. I started to sound funny and the check engine llght started to flash. It started to loose speed. First it would run 50 then it slowed to 40 then 30 and last before I towed it home from the rest of the trip 20. After some time of running will knock profusely. The cooling fans seem not to engage and I am perplex as to the cause of the problem ( fuel filter, fuel pump,
MAF sensor, throtle position sensor )

It sounds like you have a weak fuel pump, clogged catalytic converter or a bad MAF or MAP sensor but to be sure we should run the codes by checking out this guide.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

we should also go over this guide as well.

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

Please run down these guides and report back.
Joe

Will not get full capacity speed until it reaches 4,000 rpm's then it will shift into full speed. Where is fuel filter and fuel sensor located on this truck Classic model?

The fuel filter is part of the fuel pump assembly on this vehicle. I attached the detail about the fuel system for your review.

Just so I am clear on what the issue is, the vehicle stays in the same gear until it reaches 4,000 RPM's in every gear? Or are you saying that it feels like there is low power until it reaches 4,000 RPM's?

https://www.2carpros.com/articles/symptoms-of-low-engine-power

Let me know and we can go from there. Thanks

Hi,

There is no inline fuel filter for this vehicle. Check the diagnostic service codes and the data list it could have a faulty sensor causing a lean condition. Check the quality of the fuel it could be contaminated. Check fuel pressure should be 50-60 with key on. Check intake manifold vacuum should be 17 to 21 psi. if lower than specified check air intake manifold for leaks and exhaust back pressure. I'm attaching service guides below for you to reference.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

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

Okay, so just now my truck started acting up?
it felt like i lost power literally and when i start from a 0 mph roll its not running like it usually is. once i give it more gas it revs fine but the rpm and the transmission finally kick in to get it where it should be?? what could it be?

Hello,

This is common when the throttle bore needs service due to coking, here are two guides that can help us fix the problem:

https://www.2carpros.com/articles/throttle-actuator-service

and

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

Please run down these guides and report back.

Thank you for the first guide it helped me fix the problem. plus I found a small leak in the air intake tube.

Rebuild the transmission. I replaced the fuel pump, .injectors,.fuel pressure regulator,.spark plugs, wires,throttle position sensor. checked rive 5 volts good ground and I still have poor acceleration. Last I do not have catalytic converters they have been removed. Please help! Any ideas?

Without catalytic converters, no change is going to take place in the composition of the exhaust gas, so the front and rear oxygen sensors will report exactly the same readings. That is what happens when a converter has failed and is what tells the Engine Computer to set a diagnostic fault code related to that failure. The Check Engine light will be on because the fault codes refer to something that could adversely affect emissions. With the Check Engine light on, you have no way of knowing when another problem is detected. More importantly, the Engine Computer knows it can't rely on the readings from the rear sensors to provide test results for some of the self-tests it runs, so many of those tests will be suspended. You could have a minor problem that might turn into an expensive one, but there will be no way to know which circuit or system has the problem without a fault code. this guide can help

https://www.2carpros.com/articles/symptoms-of-low-engine-power

The first step is to replace the catalytic converters, erase the current fault codes, then hope a new fault code sets to direct you to the area that needs to be diagnosed.

Thank you for a response......The only code I have are P0420 and P0430 related to catalytic convertor..so I replace it and the power is back......Thank you again!

This is a truck I am looking at getting but want to know if this can be fixed relatively easily.

The truck was being driven one day in December 2018 (quite cold) when it felt like it went into neutral. It was being driven and being given gas and all of a sudden it wasn't doing anything and it started to rev low and came to a creep, basically, going 3-6 miles an hour. Right across the dash where the kilometers are displayed it said 'Low Power' or 'Insufficient Power' or something along those lines. A brand new alternator was purchased and put in but that did not change anything.

What could be the problem? Could it be as simple as the battery terminals need cleaning or re-tightening?

The truck has had regular oil changes.

Hello,

This might be an easy fix, it sounds like the truck in in limp mode this guide will help you fix it.

https://www.2carpros.com/articles/reduced-power-limp-mode

and

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

Please run down this guide and report back.

the truck needed a cat replacement all good now thanks for the information.

I have the truck listed above 2500 HD. it has lost almost all engine power. I am not sure what is wrong with it. Any suggestions would be great.

Hello,

It sounds like you could have plugged catalytic converters which is common. Here is a guide to confirm the failure:

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

If confirmed here is a video that shows how to change the catalytic converters out.

https://youtu.be/CORe9JyrexI

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

Truck just revs once it hits 3,000 rpm's and will not speed up. Drives fine in first and second gear. We changed the transmission filter but it is still doing it.

Video.

Good afternoon,

It could be a couple of things.

If the catalytic converter is clogged, it will act like this.

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

The other possibility is low fuel pressure from a bad fuel pump.

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

The pressure needs to be checked to verify.

The catalytic converter needs to be tested as well. You need a back pressure gauge to verify.

Roy

when driving on the high way truck will accelerate when going down hill but going up hill pushing down on the gas causes engine to rev up but doesn't pick up speed and the engine sounds normal. No RPM Increase, fuel filter changed to no effect. What could a possible answer be to this problem?

Your probable causes could be the MAF sensor. Please go over this guide

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

Please run down this guide and report back.

Thank you for the insight you provided. Also there is an addition to the symptoms. When causing the problem to repeat for a family member they noticed a rotten egg smell that they claimed to be the catalytic converter. They informed me that this is very possibly the cause. What do you think? I'm checking what you listed any way since you can never be to safe but i'm still interested in what you think about the converter.








[quote:723368b60a="rasmataz"]Your probable causes could be one of the following,or your tranny is slipping.

Oxygen sensor
Dirty fuel injectors (cleaning the injectors often fixes this).
Bad MAP (manifold absolute pressure) sensor
Bad TPS (throttle position) sensor
Bad or dirty MAF (mass airflow) sensor
Low fuel pressure (leaky fuel pressure regulator or weak fuel pump)
Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)
Bad gasoline (fuel contaminated with water or too much alcohol)


Sometimes, what feels like a hesitation is actually ignition misfire rather than lean misfire. The causes of ignition misfire may include:

Dirty or worn spark plugs
Bad plug wires
Weak ignition coil
Wet plug wires[/quote:723368b60a]

What you smelling is sulfur-could be the catalytic converter to find out check for excessive back pressure by using a vacuum gauge or pressure gauge if so the Cat is defective also be aware changing it and if the cause is not found it will burn up the new one-Read below and good luck

How can I tell if my catalytic converter is working properly?

This guide can help

https://www.2carpros.com/articles/how-to-test-a-catalytic-converter

I had to replace the converter cost me $1100.00 ochy

Hello my truck misses very badly at start up for 1 minute. No check engine light or codes. It does this at every start even if driven for an hr and turned off and right back on will miss so bad first minute that can not be driven. It has been doing this for 6 months. When I start it if I floor the pedal the engine will not rev above 2000 rpm and sputters and misses. I have gotten so I start the engine and wait a minute before trying to drive. I thought it was a fuel presure problem but with the guage on it presure stays between 60 and 65 lbs at all times when it is missing and when it is running properly. Help! I hate to just start guessing at parts replacement.

My concern is electrical. If the fuel pressure remains steady, it should be fine. However, there should be some fluctuation when you hit and release the gas. Also, did you check to make sure the the regulator is working properly? If you need directions, let me know. This guide can help us fix it

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

As far as the electrical, has the check engine light ever come on? Has there ever been black smoke from the exhaust when this happens? Have you checked to make sure the catylatic converter isn't plugging when first starting?

Somewhat frequently when i hop into my truck and head to the gas station It seems like im not getting gas. I'll back out of my driveway put it into drive hit the gas and it acts as if the motor wants to die. The rpm gauge will dip down but it never actually kills altogether. I can get the rpms to rebound if i let off the gas only to repeat itself. Also because of this it at times doesn't seem like its getting enough power to shift into a different gear. I can push my gas pedal all the way to the floor but its like its not getting any gas. Once i get it moving forward down the road about a mile or so it works perfectly every time. This only happens if the engine has NOT been running for a while like overnight for example. Sensor?
I did take it to a chevy dealer a couple of years ago to address this...They did witness it doing this but were unable to figure out the cause. the blew out my jets checked my fuel pump and changed the fuel filter. $330 later.... Next morning still did the exact same thing.

Any known issues with this particular truck that causes this problem?

I suggest starting with checking the fuel pump pressure. You could do it yourself to save labor. Many of the parts stores now lend or rent tools, so try that to get a fuel pressure gauge. Also, if you have never done this before, check out this video. It explains what to look for, and it shows how to perform the test.

https://www.2carpros.com/dia/test_fuel_pressure.htm

Let me know what you find.

Joe

Joe,
We have had the same issues as above. However, we are still experiencing the bog down on cold start. We replaced fuel pump and have had diagnostics hooked up to it . That showed nothing. Any thoughts?

Hello,

Yes the mass air flow sensor can be dirty causing a problem while not showing any codes.

Here is a guide to show you how to clean it.

https://www.2carpros.com/articles/mass-air-flow-service

sometimes this doesn't work due to the condition of the sensor and you may need to replace it.

https://www.2carpros.com/articles/how-to-replace-a-mass-air-flow-sensor-maf

Please let us know what you find.

Cheers, Ken

This is kind of a difficult problem to explain as it is not constant. Occasionally, my Silverado will act like it's not getting any fuel or air to the engine when I start it after it's been sitting for awhile. When I press the gas, there will be a lack of response from the engine, and often times the engine will almost die or will die until I back off the pedal. This doesn't happen very often, but this week I am in a higher elevation (about 7000ft compared to 1000ft) and it is happening worse than ever. This morning when I started it, the engine couldn't even rev up to idle and it died. When I restarted, it seemed to idle better. I am at a loss to explain what this is because it only happens when the engine is cold. Once I've been driving it around for a bit, the problem goes away. I was thinking it could be an O2 sensor, but shouldn't the ECM be running in open loop until the engine is warm? I've also replaced the EGR valve, spark plugs and wires, fuel filter, and cleaned the MAF Sensor in an attempt to fix the problem. Any help would be greatly appreciated! Thanks!

Hi
Check the Engine Coolant Temperature sensor located by thermostat housing. Ohm check at 68 deg. should have 3520 ohms of resistance.

this guide will help us fix the problem

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


Let me know
Thanks for donate

check for an intake manifold leak. the gaskets were prone to leaking and have been redesigned. if you have access to a scanner, compare "MAF" with "Desired IAC airflow" - should be pretty close to each other. you can also look at fuel trim - but its not always obvious. sounds like your problem - once truck enters closed loop it can easily compensate.

this applies to silverados with 4800 and 5300 - not older c/k with 5.7 - made both in 1999

I have no power at low end on my truck. I hit gas and it delays and can’t even roast tires when trying engine just bogs down. it has a new MAP, MAF,TPS, fuel pump, fuel filter coolant, temperature sensor, catalytic converters, cold air intake, muffler, rebuilt transmission and tuned. I’m lost on what it could be. no vacuum leaks steady idle.

Good morning,

Several items could contribute to this.

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

1. Fuel pressure. Low fuel pressure will give you low power.

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

2. Catalytic converter partially clogged not allowing the engine to breathe.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

3. Timing. Since the truck is a 1999, you could have a worn timing chain changing the timing between the crank and the cam.

https://www.2carpros.com/articles/serpentine-belt-timing-belt-timing-chain-diagrams

5. What stall speed torque converter was installed at the rebuild? An 1800 will not give you power off the line. You need around 2200-2500 for a fast start.

Roy

It hesitates when starting, it bogs down upon acceleration but eventually gets going. seems to bog worse going uphill. terrible gas mileage, sputters. Please help!

This sounds like either an air flow issue or a sensor issue.

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

Before we go to far, let's check codes and see if we have anything.

If not, try to monitor fuel pressure as well. Without any codes, we are going to have to just start checking each of these systems. Air filter, throttle body is dirty, exhaust restriction, fuel pressure.

My question is the last few days when i have been in my truck and i try to accelerate especially going uphill all i get out of my truck is no power it bogs down it almost feels like the transmissionn but there is no slippage? Got any ideas?

if it was slipping the rpms would be climbing up but since they aint id suspect engine issue.

This guide can help us fix it

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

try replacing the fuel filter and run some fuel system cleaner through it to clean up the engine. then check your maf sensor for proper operation