My car doesn’t want to go up hills. It has slow acceleration, and feels like it’s not kicking into the next gear when I drive it.

When I first start my car I have no issues. It idles fine, but when I'm accelerating it feels like it doesn't want to go to the next gear. I've replaced the spark plugs and wires and put a new fuel filter on it. We checked the fuel pump, but the car doesn't die out when i go up hills. When I push it to try to make it change gears the car stalls and I can hear a sound like air escaping in tiny little puffs. I've been putting fuel injector cleaner in it and it helps a little but I have no power in my car, sorry if I sound crazy.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Hi There,
What you are describing sounds like you may have a clogged catalytic converter. The catalytic converter converts toxic exhaust gases into less harmful pollutants that are suitable to be expelled into the atmosphere. When the catalytic converter is clogged, this causes these gases to be backed up into the exhaust system not allowing the engine to breathe properly. When this happens, the engine is forced to work much harder to expel these gases. This often results in the engine bogging down, hesitating, shaking and causing very poor fuel economy. This should also cause a check engine light to come on as the O2 sensors should be reading the incorrect amounts of oxygen in the exhaust gases if this is your problem. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your catalytic converter.

How to Identify and Fix Common car Problems ?

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Clogged fuel filter

When the fuel filter is clogged, the fuel pump has to work much harder, resulting in a far less efficient drive. This means you can`t get the power you need if you`re trying to accelerate when overtaking or going uphill.

There are several causes for your car to lose power significantly while accelerating. The most typical causes of a car not accelerating while driving include a faulty sensor, contaminated fuel or air filters, or a faulty timing belt.
Culprits include a dirty fuel filter, clogged fuel tank strainer, clogged or failing fuel injectors, or a defective fuel pump. On most vehicles replacing the fuel filter is a DIY operation.
Clogged Fuel Filter

When you press down the accelerator pedal and get minimal output, it could mean you have a problem with your fuel system. The most probable issue is a clogged fuel filter. Your fuel filter works to ensure that dirt and debris do not get into the fuel system.

You will feel a loss in power while accelerating and at times intermittent jerks. To solve this issue find the fuel filter located in the engine bay or near the fuel tank in your car`s trunk. If the fuel filter is clogged replace it if you have the skills to do so or get it changed at your local mechanic shop.
One of the most common causes of a sputtering engine is an issue with the vehicle`s fuel system—the filter, pump, and injectors. These three critical components work together to ensure fuel flows smoothly from the fuel tank to your engine`s fuel injectors, and then pumps into the engine evenly.
Fuel System Issues:

A poor fuel delivery drains out the power of the engine resulting in poor acceleration. Fuel filter – A dirty or clogged fuel filter affects the fuel supply to the engine and thus the engine has low power causing poor acceleration. Other parts of the fuel system are the fuel injector and fuel pump.

The car can feel sluggish and heavy when there is a clogged air filter, a dirty fuel injector, or a problem with the oxygen sensor. A catalytic converter that is going bad can also make the car feel sluggish and heavy. The spark plugs may also be worn out or damaged, causing the car to lack power.
Rough starts, hesitation and poor acceleration are all common symptoms of a bad spark plug. If a spark plug or multiple spark plugs are faulty, they will have trouble creating the spark that causes the ignition process in your vehicle.
Worn Transmission Fluid (Automatic Transmission)

Over time, the transmission fluid gathers dirt and grime. This can cause the engine to run roughly, stall or fail to accelerate when you press down on the gas pedal. You may need to have a transmission fluid change before more damage is done.

Typically when the car will not accelerate past 60 MPH, it`s due to either the ECU activating a limp mode or other mechanical (fuel or ignition system component) failures.
One of the most common causes of jerky acceleration is a dirty fuel injector. Your fuel injectors are responsible for pushing fuel into your engine`s cylinders. This means they control the timing and amount of fuel used to keep your engine running.
This hesitation while accelerating can be the result of a number of issues, including something like a clogged fuel filter or even a broken fuel pump. Sometimes, something could also be wrong with the transmission.
With the fuel pressure gauge attached, start the engine and let it idle. Disconnect the vacuum hose from the pressure regulator; the pressure should drop approximately 8 to 10 PSI. If it does not, suspect a problem with the regulator or its` vacuum supply.
A bad fuel pump may overheat and inadequately deliver gas to the engine, causing it to run hot and turn off while on the road. In this scenario, your vehicle may start back up after overheating and shutting down, only to do the same thing a half-hour later. This scenario is a common sign of a bad fuel pump.
The most common signs of bad spark plugs include start-up trouble, rough idling, sluggish acceleration, declining fuel economy, engine misfiring, and engine knocking.
“Limp Mode” – If your car won`t accelerate over 25 or 40 mph, it could have engaged `limp mode. ` It is also known as a limp home mode, and it acts as a preservation feature. It is meant to get you home, to an auto mechanic, or safely off the road without destroying your engine.
Among common possibilities for loss of power are throttle body faults (electronic throttle controls, mass airflow sensor, torn air intake hose), worn out spark plugs, faulty fuel pump or restricted fuel system, and large vacuum leaks (including EGR malfunctions, PCV system, leaking intake manifold, leaking EVAP purge …
Worn Transmission Fluid (Automatic Transmission)

Over time, the transmission fluid gathers dirt and grime. This can cause the engine to run roughly, stall or fail to accelerate when you press down on the gas pedal. You may need to have a transmission fluid change before more damage is done.

Typically when the car will not accelerate past 60 MPH, it`s due to either the ECU activating a limp mode or other mechanical (fuel or ignition system component) failures.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

My car doesn’t want to go up hills. It has slow acceleration, and feels like it’s not kicking into the next gear when I drive it.
ANSWER : Hi There,
What you are describing sounds like you may have a clogged catalytic converter. The catalytic converter converts toxic exhaust gases into less harmful pollutants that are suitable to be expelled into the atmosphere. When the catalytic converter is clogged, this causes these gases to be backed up into the exhaust system not allowing the engine to breathe properly. When this happens, the engine is forced to work much harder to expel these gases. This often results in the engine bogging down, hesitating, shaking and causing very poor fuel economy. This should also cause a check engine light to come on as the O2 sensors should be reading the incorrect amounts of oxygen in the exhaust gases if this is your problem. I would recommend having an expert from YourMechanic come to your location to diagnose and replace your catalytic converter.

It feels like my car is about to break down, like I am very carefully carrying the engine home so it doesn’t fall out.
ANSWER : Hi there. I would typically start by checking to see if the check engine light is on and then I would scan the computer for codes. This can give some insight as to what is going on. If there are no codes then I’d monitor the signal from the sensors to make sure that they are all working fine. If those are also fine then the issue sounds like it may be a catalytic converter or a transmission problem. This vehicle has a history of transmission failures that could cause this. Also, if the catalytic converter fails it will cause the same symptoms. I usually test the converter for any signs of failure and do a back pressure test of the exhaust before getting into the transmission. If you’d like assistance in diagnosing this issue, a certified YourMechanic technician can inspect these issues with your engine hesitating and help diagnose your vehicle.

Your issues with the air conditioning unit are likely unrelated to the issues with your engine, and you will likely need your AC unit inspected in order to diagnose that issue.

My manual car won’t go into gear, it turns on and the clutch goes down perfectly fine. It happened after my gears grinded, the car
ANSWER : If the clutch mechanism is releasing properly, and the shift linkage is not malfunctioning, your transmission will have to be removed from the vehicle and inspected. Once a transmission has been removed from a vehicle, if the problem is a broken or worn part or parts, and the transmission has 100,000 miles or more, the most cost effective approach is to just simply rebuild the whole transmission. There are transmission rebuild kits that are sold just for this purpose. Rebuilding a transmission is no big deal and is indeed easier in many respects than rebuilding an engine. You can rebuild your transmission right in your own garage. You can NOT rebuild an engine in your own garage due to the highly specialized, and extremely costly, machine shop equipment required. Occasionally, mobile mechanics will take on a transmission rebuild job especially as once the mechanic removes the transmission from the vehicle, it is just simply a modular unit that can be easily transported to a mechanic’s shop and rebuilt right there and then returned to your vehicle. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

Feels like car isn’t shifting into second gear, cant go over 20mph in drive.
ANSWER : There is an issue with the transmission is the main valve either is disconnected inside the transmission oil pan on the controller or the controller has an internal leak or a check ball is not holding. I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your transmission.

Started Three days a go. When I drive the car it doesn’t go in to gears but shows AT.
ANSWER : This kind of reaction is often a sign of low transmission fluid or a faulty transmission control solenoid. As you know, automatic transmissions use pressurized hydraulic fluid to change gears. Every time a gear change is required, the car’s computer activates a transmission solenoid, which directs transmission fluid into the valve body to engage the correct gear. When this is faulty or not working properly, this can cause a delay in gear shifting or in some cases cause the car to not shift at all. This type of problem is amplified any time the transmission is low on fluid creating a drop in hydraulic pressure. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

Car doesn’t want to stop when brakes are pressed, has an odor, and feels like it wants to power off on me.
ANSWER : Hello.

From what you describe it would appear that some sort of serious issue may have occurred that is greatly affecting engine performance. A few common reasons why a car would not want to go over 45 mph is due to problems with the fuel, ignition, or engine management systems. Smoke from the engine is usually a result of fluid leaks. It may be possible that oil, power steering, or even brake fluid are leaking and have made contact with a hot engine component, producing smoke. You mention that the car did not want to stop, or had trouble stopping – this could be related to the smoke if there is a brake fluid leak present. I would recommend having a professional technician look at the vehicle, as the possibilities could be many.

Regards,

Eduardo
YourMechanic

Shifting from 2nd to 3rd, car stopped going fast. Now it won’t go at all.
ANSWER : It is possible that your clutch has failed. The sound you are hearing is likely due to the clutch not engaging with the engine due to it being worn. I would recommened having your transmission inspected by a qualified transmission expert to determine if your clutch requires replacement in order to resolve this issue. This inspection may require removal and partial disassembly of the transmission in order to verify that the clutch has failed.

Car won’t go into gear. 2002 Audi A4 Quattro
ANSWER : Hi there – Your symptoms describe the behavior to expect when your clutch hydraulics go out (clutch master and clutch slave cylinders). Check your clutch fluid level – it may be low. If the fluid level is low, this usually means your clutch slave cylinder has worn out, not unusual with your mileage, and should be replaced. I recommend a malfunctioning clutch inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.