Engine loses power

Most likely cause is the generator. They develop huge voltage spikes that destroy the internal diodes and voltage regulator and they interfere with the computer sensor signals. With one bad diode of the six you will only be able to get exactly one third of the rated current and that's not enough to meet the demands of the electrical system under all conditions. It is common to go through four to six replacement generators in the life of the vehicle. To reduce the number of repeat failures, replace the battery at the same time unless it is less than about two years old. As they age they lose their ability to dampen and absorb those spikes.


This guide can help


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

Please run down this guide and report back.

When I attempt to accelerate the vehicle won't allow me to press the gas pedal very much. It hesitates and as I left off the gas, I can slowly increase my speed.

Sounds like a plugged exhaust. Easy to run a pressure test on it.

Could also be a plugged fuel filter.

I have a 2000 Jimmy 128k. I loose power & get a miss fire code under load. when I tow up a hill start feeling loss off power. Almost dies. Also happens cold when going up a hill. Changed the obvious (plugs, cap, rotor, also cam & crank sensors) and use only Delco parts

Have the fuel pressure checked. You could have a clogged fuel filter affecting the fuel supply resulting in loss of performance.

If the Malfunction Indicator Light is shoiwng, get a scan to cehck for trouble codes.

Checked fuel line, it had some fluxuations. Changed to a Delco fuel filter. First day out up inclune in road (first 10 mins) idoit light on Misfire

What is the trouble code?

P300 random misfire (90%) cyc 4 10% but I think that was by chance

Basics have been covered so you need to go further into diagnostics.
Have you checked the fuel pressure and air filter ?
Try cleaning the MAF.

after warm up, acceleration is choppy, almost choking. if I baby the accelerator, can get it to go. No exhaust problems, new fuel filter, fuel pump 3yrs old, no codes coming up. replaced injection assembly. this helped somewhat. still had choppy acceleration after warming, once it was stopped and restarted. all indications when running and diagnostics hooked up show every thing should be ok. any suggestions? thank you

Have you checked for vacuum leaks? Also, even though the fuel pump is 3 years old, you may want to check fuel pump pressure at the fuel rail. You could have too little or a bad regulator and too much.

Let me know.

Joe

My car keeps losing power brand new battery and the alternator could it be the fule pump. and how do i replace it?

How is it losing power? Electrical or engine power?

If it's engine power does it rev freely when you shift to neutral? Does the exhaust note sound the same?
With it in gear and you step on the throttle what does it do?


It could be many things depending on what your answers are.

engine losses power as I drive down the road RPM will not go up and when they do it feels like I just down shifted and rpms drop as soon as I release the the pedal the rpms go up about 500 to 1000 rpms soon i can not go faster than 5 mph and it starts to back fire if i shut the engine off for a few minutes i can start with no problem and drive for a few minutes till it starts over. uuu

Could be one of the following below that's causing it

Oxygen sensor
Catalytic converter
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

I'm looking at buying a 98 GMC Jimmy. It has over 210,000 miles on it but well kept. Problem is it won't go over 30 miles per hour. What would be the causes of this? I'm thinking most likely a speed sensor but not really sure. Drives fine until I get up to 30 mph.

scan for codes and check fuel pressure then check vacuum at idle if 15" or below suspect clogged converter.

my gmc 98 jimmy has been having some acceleration problems where the rpms will jump up and down when I'm in the top gear? i replaced the throttle position sensor and that didn't really work, not sure what else it could be?

Is the check engine light coming on at all? If not, then it sounds like the transmission may be slipping.

No the check engine light hasnt come on at all. it feels like the rpms only jump up and down when I'm sitting at 40mph?

Electrical problem
1998 GMC Jimmy 6 cyl Four Wheel Drive Automatic alot miles

while cranking the engine I will lose power for about a second or two then it will go back to cranking normaly and the whole things starts over again. The engine will start if I get lucky

I would start by making sure your battery cable's are clean and tight.Then i would have the battery and alternator tested.

Engine Performance problem
1997 GMC Jimmy 6 cyl Four Wheel Drive Automatic

Heres the problem. So my car starts fine, when i go down the road a few miles and it shifts from 1st and 2nd ok, then the take jumps up to round 3000 and I have a loss of power but it still is going but not much power. I pull over and start again and it is fine till it shifts out of 2nd. After 2 days it gave me a check light and it said rear o2 sensor. Any thoughts?

It sounds like you may have some transmission issues. I would get it checked by a competent trans shop that can access any stored codes that your code reader can not.

i bought this jimmy and when you start it up it sounds fine but when you start to drive it has no power but when it warms up you would think it is a new one any info!!!!!!!!!!!!!!!

maybe the coolant sensor?

how do i go about checking that

any coments people???

I have a 97 jimmy I was driving on the interstate and the cruise kicked up the motor. After that it has been running really ruff and dies at a low idle runs good at high rpms in park but when u put it under load it has no power. I have change the plugs and cat converter , no check engine lights. I am at a loss with it.

this could be anything, spark plug wires/ the injection spider in the intake manifold. Have a pro look at this before you spend unecessary money on things that you are guessing at....

My 96 GMC Jimmy Has been Running Quite Weird Lately, The Engine Light Keeps Blinking Continuously, It Runs & Moves, But The Problem Is That It Does'nt accelerate Properly When I Push Down On The Gas Peddle? Like I Mean It Does'nt Stall Out, It's Just Like The Vehicle Is Not Getting Any Fuel, Power Or Something???

If the check engine light is flashing, there is an engine misfire. Yes, that will cause a power loss. However, you need to determine what is causing the issue. Start by having the computer scanned so I know which cylinder or cylinders are causing the problem. Most parts stores will do it for free.

Do that and let me know what you find.

i have a problem trying to accelerate it bogs or hesitates and it does not ever come back up i have changed the spider ,fuel pump fuel filter ,02 sensor i am at aloss trying to go from here any suggestions

Test the fuel pressure, it should read 60-66 psi. Also the throttle position sensor and the manifold absolute pressure sensor.

When was the last tune-up?
Could be a weak ignition coil.

The fuel pump which was replaced right before my posting was messed up due to some bad gas. We replaced it again & it's working fine now. I was ASE certified in engine repair & am in the processd of getting my CAT(erpillar) certification through a local college so it's not like I don't know anything about cars. I work on semi trucks & heavy equipment for a living & have been doing it for the last 25 years. I was just at a loss the day I posted the problem considering I had replaced the fuel pump, fuel filter, the fuel injector & the 02 sensor & 2 days later it started doing it again. I do appreciate the effort anyways.
Thanks
Tom

Vehicle started losing power at take off and low speeds. When I stopped to check it out the was a fuel odor and fuel in the oil. What could be the cause for this?

If you have tbi fuel system, look to see if injector/s are leaking? Any visible gas leaks under the hood, under the vehicle? Check the pcv system.

Sometimes you can smell gas, undewr the hood, if there is an issue with evap system.

How long since a tune-up? Any applicable mil codes?

Its a multiport injection system The gas smell seems to becoming from the exhaust and from the oil which was about a quart over when I checked it.

You can use a fuel pressure gage. See if pressure will hold for bit, everything off. Check the vacuum line for fuel pressure regulator, any gas in it?

Engine Performance problem
1992 GMC Jimmy 6 cyl Four Wheel Drive Automatic Unknow miles

I have a 1992 GMC Jimmy. When I step on the gas, it is a real struggle to accelerate. I have owned one before just like it, and it accelerated great. I'm thinking my fuel injectors are going out. I have already replaced the fuel pump previously, so that is all I can come up with. I'm wondering also if it has the spider or the cylinder with two stems? And, is it hard to fix myself? It is the regular jimmy that looks just like a blazer. Thanks for your help.