Hey when the car idles it revs up and down by like 300 revs or so and also when the car is off it doesn’t recognize its in park.
When I switch off the car (it's push to start) the car doesn't recognize its in park so when I get out the car keeps beeping and I have to disconnect the battery to stop it , what do you think could be the cause of this also with the transmission revving up while idling?
My car has 155000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
The issue is the transmission position sensor is not working properly and registering that the transmission is in drive, neutral, or reverse. Check to see if the transmission is going into park when the shifter is in park. If the transmission is going into park, then the sensor is not working and needs replaced. If the transmission is not going into park, then the shifter cable may be broken or out of adjustment. If you need further assistance with transmission not going into park issue, then seek out a professional, such as one from Your Mechanic, to help you.
How to Identify and Fix Common car Problems ?
Our sources include academic articles, blog posts, and personal essays from experienced mechanics :
Among the potential underlying causes are vacuum leaks, EGR system malfunctions, malfunctioning oxygen sensors, dirty fuel injectors, fuel pump malfunction, faulty spark plugs, a faulty mass airflow sensor, or a faulty throttle position sensor.
Automatic vehicles use speed sensors to determine when the gear should be shifted up or down. In the event that a speed sensor doesn`t work correctly, your car might not shift gears when it needs to. This can cause high RPM as the engine has to work harder.
This may be a sign of a failing throttle position sensor. The throttle position sensor (TPS) is a sensor used to monitor the throttle position of the throttle plate inside the throttle body in relation to your foot position on the gas pedal.
Typically, the idle speed will be set at a value in the range of 600 to 800 RPM, but the exact value will depend on the number of engine cylinders and whether the vehicle is equipped with a manual or automatic transmission.
Replace the sensor with a compatible one and correctly install the crankshaft position sensor to ensure that the engine runs optimally and safely. A qualified technician can prevent further issues with RPM fluctuations while driving by installing the sensor correctly.
Worn Spark Plugs or Spark Plug Wires
Your vehicle may experience misfires and jerking while accelerating. Similarly, if spark plug wires or ignition coils have expired, the vehicle may experience a similar behavior to bad spark plugs.
Automatic transmissions that shift hard, jerk or shake during a shift change may mean your transmission fluid needs changed or fluid level is low. In manual transmission vehicles, abnormal gear shifts could indicate damaged gear synchros, worn clutches or other, more severe issues.
Most often, over-revving occurs not because of a deliberate attempt to push a vehicle, but rather as a result of missing a gear while shifting. When a manual car accidentally downshifts, a rev limiter will not be able to react quickly enough to prevent the engine from over-revving.
The idle speed should feel consistent without skipping or slipping. In most of today`s cars, an idle speed of 600 to 1000 RPMs is average. If your car is idling rough, though, it won`t feel smooth. The RPMs will jump up and down, for example, or they`ll fall below 600 RPM (or whatever is typical for your vehicle).
The idle control valve is usually located on the intake manifold near the back of the throttle body.
Typically, engines idle at about 600-800 rpm. Older engines may go up to 1200 rpm or more while warming up. But if the engine is revving up while idling, even after it`s sufficiently warmed up, you might have a problem.
You can check to see if you have faulty wiring by using a voltmeter. Keep your engine idling and then test the wires with the voltmeter to see if there are any inconsistencies. Your mechanic can easily perform this test for you. If the wires are fine, then the gauge itself might be damaged and may need to be replaced.
What RPM should a car drive at when accelerating? When accelerating your vehicle, it is best to stay within a 2000-2500 RPM range. This will give you enough power to reach an acceptable speed level while also ensuring the engine stays within safe operating limits.
The problem may involve an annoying change (up/down) of engine speed while cruising at a steady pace, a low drop (or even cut-out) at idle or when approaching a stop, a wild high engine speed of several thousand rpm followed by a drop to near zero, etc.
If you notice a large delay between going into gear or between shifting gears where your engine is revving really high before it shifts, it may point to several problems with your transmission: Transmission Solenoid problems. Engine problems. Low or dirty fluid.
This is usually caused by troubles with the vacuum, transmission fluid or a faulty sensor. The vacuum modulator valve helps older vehicles determine when to shift gears. There`s a hose that connects the valve with the intake through a hose.
Improperly functioning spark plugs cause an uneven burn of fuel in the engine, resulting in fluctuating RPMs and a louder noise. You might also experience increased vibrations of your vehicle while sitting idle or while traveling at low speeds.
The IAC valve is controlled by an input signal from the ECU as required by the engine management system, the duration and frequency of the ECU input signal determines how long and how far the IAC valve opens, hence the amount of air that is allowed to bypass the throttle plate.
The most common cause of the shaking most often happens near your tires and rims. The tires and wheels connect your vehicle to the road, and if anything is a bit wonky, will notice. It may be something like a broken transmission or a broken control arm.
Normal idle speed for your vehicle, once the engine is warm, should be around 750 RPM (roughly). Two thousand RPM is significantly out of range high, even for a cold engine. The occurrence of this high idle speed might be a coincidence and thus not related to the alternator repair.
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.
Yes. While the damage may seem small initially, the longer you drive with a bad oxygen sensor, the worse the damage will become. Eventually, you may experience rough idling, poor acceleration, engine misfires, an illuminated check engine light, and failed emission tests.
With the idle mixture screw removed, the tapered portion is what adjusts the volume of fuel allowed into the engine. Turning this adjustment screw clockwise (in) reduces the amount of fuel. Turning the screw counter-clockwise (out), increases the amount of fuel delivered to the engine.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
Hey when the car idles it revs up and down by like 300 revs or so and also when the car is off it doesn’t recognize its in park.
ANSWER : The issue is the transmission position sensor is not working properly and registering that the transmission is in drive, neutral, or reverse. Check to see if the transmission is going into park when the shifter is in park. If the transmission is going into park, then the sensor is not working and needs replaced. If the transmission is not going into park, then the shifter cable may be broken or out of adjustment. If you need further assistance with transmission not going into park issue, then seek out a professional, such as one from Your Mechanic, to help you.
Car is idling at high rpm’s and when the days are hot the car cranks but doesn’t turn on and also exhaust is smoking when i rev it
ANSWER : Hello – your symptoms suggest worn piston rings or valve stem seals (smoking), and a possible air leak in the intake, or idle air control valve sticking open (high idle). Both are signs of a higher-mileage engine with significant wear. I recommend an engine inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
Car is new nissan versa warm up car idles down then shoots back up like something is kicking on then idles down then revs back up
ANSWER : Hello. Depending on the road you are driving on and if here is extra weight in the vehicle then this can occur. This is usually compensation for the lack of power that the engine puts out. With that being said it should be minimal. If it is very noticeable then you may actually have a programming issue or a faulty throttle body. Both are common on this vehicle. It sounds like the vehicle is still under warranty so I would take the vehicle to the dealer.
Car doesn’t accelerate
ANSWER : This may be a sign of a faulty MAP sensor as the vehicle responds adversely to a load put on the motor (i.e. putting it in gear, turning on AC or engaging the brakes). The Manifold Absolute Pressure (MAP) sensor senses engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The engine computer then uses this information to adjust ignition timing and fuel enrichment. When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the MAP sensor, it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance. This may also be caused by other closely related components such as a dirty or failing mass air-flow sensor, a faulty throttle position sensor or potentially a vacuum leak. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
Car shifts hard and rpms rev high on there own or car doesn’t shift at all, ABS and traction control lights are on also. 2005 Chevrolet Cobalt
ANSWER : Hi there – first task is to be sure the transmission fluid is at the proper level, and in good condition (more pink than black, and no burned smell). Low fluid, or dirty fluid, can cause lots of unexpected transmission behavior. The second task is to check for problem codes, whether the Check Engine light is illuminated or not. The possible problem we’re looking for here is a failing throttle position sensor – which interacts with the transmission controller and affects shifting behavior. I recommend a transmission inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
I pulled into a parking spot and put my car into park, when I lifted my foot from the brake the car continues forward.
ANSWER : The vehicle transmission did not get back to the park position due to the shift cable came off of the transmission shift linkage. You will need to have a mechanic like one from YourMechanic come to you and check the shift cable connection at the transmission to see if the shift cable bushing broke and let the cable end disengage from the shift linkage. The shift cable may need replaced if the cable end bushing is not available. I recommend a mechanic check the shift cable and replace cable or repair cable end as parts allow.
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.
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.
Stays idling when I put it in gear, and the car doesn’t move. When forced into any gear without the clutch, the car does not shut off.
ANSWER : Hi there. The clutch may be worn and slipping causing the engine to stay running as the shifter is put into a gear selection. If the clutch was working, when put into gear and let off the clutch pedal, the vehicle will either move or stall out the engine. Check the slave cylinder and see if the return spring has broken off causing the clutch fork to stay engaged. Also the clutch adjuster cable could be out of adjustment or damaged. If the pedal and hydraulic assembly has no issues, then I recommend seeking out a professional, such as one from Your Mechanic, to help you diagnose your clutch.
