Car won’t go over 35 mph

My car just cannot run faster than 35 mph. Each time I apply the gas pedal, the engine would rev but there would be no increase in speed. I had the airflow sensor replaced as I was told at the shop that it would help, but I still have the same problem. What should I do?
Experienced mechanics share their insights in answering this question :
Hello. We’ll be happy to help with your 1998 BMW 318i. Your power loss may be due to something like a clogged catalytic converter, a bad ignition module, or faulted spark plugs. Check the flow of the catalytic converter, inspect the condition of the spark plugs, and test ignition module both visually and with a multimeter. To have the fault verified, you could have a certified technician inspect your vehicle’s loss of power in order to make the correct repair.

How to Identify and Fix Common car Problems ?

Our sources include academic articles, blog posts, and personal essays from experienced mechanics :

A bad MAF sensor can cause your vehicle to experience poor drivability issues such as engine stalling, jerking or hesitation during acceleration. This could happen while speeding up on the highway on-ramp or cruising down a city street.
Starting Trouble

A malfunctioning mass airflow sensor can also make it difficult to start your automobile. This can be due to the air and fuel in balance in the combustion chamber or because the main computer chip has received an error code from the sensor and does not want to start your car.

Why does my car not accelerate when I push the gas? A car not accelerating properly can be caused by a number of things. It could be due to the throttle body, gas tank, spark plugs, or the ECU. It could also be because you have a dirty air filter or a clogged fuel filter.
The oxygen sensor problem is the number one reason cars are slow to accelerate. The oxygen sensor is responsible for monitoring the air-to-fuel ratio in the engine, and over time it can become dirty or damaged, which will decrease power. Oxygen sensor malfunction will result in a mixture being too lean.
Check engine light on – When the mass airflow sensor is not working properly, too much air could enter the engine and not enough fuel. This can trigger the check engine light on your dashboard. Engine stalling – A malfunctioning MAF sensor can cause the engine to stall or die unexpectedly.
To identify the source of any MAF sensor faults, consider the following steps: Conduct an electronic test of the MAF sensor and read any fault codes using a diagnostic tool. Check the connector for a correct fit and good contact. Check the MAF sensor and measuring elements for damage.
Bad Sensors

One common culprit for this problem is the crankshaft position sensor, which measures the position and speed of the crankshaft. The computer uses the information from this sensor to know when to fire the spark plugs. If the sensor isn`t working, the spark plugs won`t fire, keeping the engine from starting.

Without a proper signal from the mass air flow sensor, the powertrain control module (PCM), which manages the engine, transmission, and other systems in your car, won`t know how much fuel the engine needs. This can either cause the engine to run too lean (too little fuel) or too rich (too much fuel).
Cleaning the MAF as part of regular routine maintenance can help reduce and/or prevent these problems. If the MAF sensor is at fault, cleaning it can help, and many times, even solve the problem. This can be done at home. You just need to remove the component, clean it, and reattach it to your engine air intake system.
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.
A loss of power is most apparent when you`re accelerating, and can be due to a number of reasons including air flow into the engine, fuel flow and even faults with the exhaust system.
The most likely issue is that a component is clogged. A clogged fuel filter is the most common reason, although a loss of power in your car could also indicate problems with the fuel pump or fuel line. Impurities or debris may be blocking the system, which causes the loss of power in a car.
The accelerator pedal sensor transmits the position of the accelerator pedal to the engine control unit.
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. Generally, this isn`t something you should ignore.
Contamination is a key reason why MAF sensors fail and require replacement. As air, dirt and other debris get into the sensor, the parts become contaminated and fail. Drivers often notice sluggish performance, rough idling, poor acceleration or even stalling. There may also be a more frequent need to refuel.
The mass air flow sensor itself is an on or off type of component, meaning it either works or it won`t. It doesn`t take time for the sensor to `break in`. The issue that can take time is if an error code is stuck in the ECU, has not been removed – yet the component is replaced.
Output signal of MAF, made by BOSCH is a variable voltage in the range 1 – 5V, whose value depends on the mass of air flow through the sensor. At zero air flow (engine stopped) the sensor output voltage should be equal to 0.98V – 1.02V.
Yes, the MAF sensor should be calibrated for the injector size. And yes, at some point you`ll likely have to increase injector size if you keep adding horsepower. At that point, you`ll also want to match the MAF sensor up to the increased fuel injector size.
Without a proper signal from the mass air flow sensor, the powertrain control module (PCM), which manages the engine, transmission, and other systems in your car, won`t know how much fuel the engine needs. This can either cause the engine to run too lean (too little fuel) or too rich (too much fuel).
Without a proper signal from the mass air flow sensor, the powertrain control module (PCM), which manages the engine, transmission, and other systems in your car, won`t know how much fuel the engine needs. This can either cause the engine to run too lean (too little fuel) or too rich (too much fuel).
If you unplug the mass air flow sensor the car will start. If you try to plug it in while it`s running the car will die.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

My car won’t go past 35mph
ANSWER : Hi there. From the description you provided, your vehicle has problems with the transmission again. You stated it will not shift into 3rd gear again, like before the transmission was rebuilt. If the transmission is again the problem, it should be covered under warranty. It could be a faulty shift solenoid. The shift indicator not reading properly could be a faulty transmission position sensor. If this is an overall lack of performance issue, according to your last statement, then possibly you have a restriction in the exhaust system. I recommend having your vehicle’s problems inspected and diagnosed by a certified technician from YourMechanic.

Read Full Q/A … : Car won’t go over 35 mph

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.

Read Full Q/A … : Car won’t go over 35 mph

My car is hesitating / jerking at speed intervals of 20 mph, 30 mph, 35 mph and 40 mph.
ANSWER : This may be a sign of a dirty or failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected into the motor. When this fails, this can cause an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This may cause a hesitation, loss of power or jerking reaction when this sensor is malfunctioning. When this is not working properly, you may also notice a strong smell of fuel. I would suggest having a professional from Your Mechanic come to your home to diagnose your mass air flow sensor.

Read Full Q/A … : Car won’t go over 35 mph

My windows won’t go down, my instruments don’t work, my car won’t go in park without shift release
ANSWER : Hi, thanks for writing in. In most cases, the problems you’re describing are caused by damage to the electrical system either at the fuse box or through relays that send electrical signals to each component that isn’t working; such as your power windows, instrument panel and others. If the vehicle was exposed to lots of water, this may have damaged the electrical system or the vehicle’s on board computer as well. The best way to reduce the stress, time and money on trying to find the exact source of your problems is to have one of our local mechanics inspect your Honda Accord for electrical problems at your home or office.

Read Full Q/A … : Car won’t go over 35 mph

Car struggles to go up hills and only goes 40-60 mph depending how steep the hill is. What’s wrong with my car?
ANSWER : Hi there:

Anytime a check engine light is illuminated it’s because a sensor has detected a mechanical or electrical fault that impacts the vehicle’s performance. If the mechanic you go to hasn’t completed a check engine light inspection; which means they actually download these error codes; then you should find a different mechanic who knows how to complete this basic diagnostic step. In order to effectively diagnose the source of your Nissan’s acceleration issues, you might want to have one of our mobile mechanics complete a car is slow to accelerate inspection; which will allow them to download those error codes first and determine why your Nissan is sluggish on hills.

Read Full Q/A … : Car won’t go over 35 mph

I bought a used car 2010 nissan versa and when I go uphill it slows down alot. When going uphill it says go 60mph I am at that sp
ANSWER : Hi there. When a car is slow to accelerate it can be caused by multiple issues, ranging from fuel systems that are clogged or damaged to an ignition system component failure. It is also possible that something in the driveline system is dragging which causes the lack of acceleration. Since there are so many different possible issues, the best way to start the diagnosis process is to have a professional mobile mechanic from our team come to your location and complete a car is slow to accelerate inspection.

Read Full Q/A … : Car won’t go over 35 mph

Idles fine in park But won’t rev above 2,000 rpm and won’t go over 30 mph. 1988 Pontiac Grand Prix
ANSWER : Hello. This can be caused by a number of things. I usually start by doing a compression test on the engine first. If the compression is low then the engine may be worn or it may need a timing chain. If the compression is fine then I test the fuel pressure and the catalytic converter. Low fuel pressure or a clog in the converter will both cause this. There are a number of other things that can cause this also. If you are thinking of having this looked at, consider YourMechanic, as a certified mechanic can come to to to diagnose why the car has no power and misfires.

Read Full Q/A … : Car won’t go over 35 mph

Car died while driving so I replaced the alternator and battery and car won’t attempt to turn over. What else could it be?
ANSWER : The initial failure was likely caused by a sudden fuel system (e.g., failed fuel pump) or electrical (including ignition) faiure. Prior to performing diagnostics be sure you have a fully charged battery that passes a load test. Then, confirm that the engine immobilizer system (security system) is not activated thus preventing the car from starting. If the starter motor is not functioning, check for power to the starter motor when the key is held in the "start" position. If there a large voltage drop at the starter motor or no power at all, you may have a faulty ignition switch but you do have to check out the entire starter circuit, which includes grounds, wiring (some of which is very heavy cabling), fuses, relays, the ignition switch and terminations. On the other hand, if the starter motor is getting power but the starter doesn’t work, then the starter is condemned and replaced. If you desire that a certified mechanic resolve this, please simply request a no start diagnostic and the responding certified mechanic will get the problem diagnosed and repaired for you. Please let us know if you have further concerns or questions as we are always here to help you.

Read Full Q/A … : Car won’t go over 35 mph