1999 gmc pickup, acts like it is not firing on all cylinders randomly
Car acts like it is not firing on all cylinders randomly
My car has 149000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
Engine misfires can be caused by many different problems and are generally caused by either a spark or fuel issue or in some cases, a combination of both. Spark related problems generally will result from things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition modules not working properly. When the misfire results from a fuel related issue, this is commonly related to a lean fuel condition (lack of sufficient fuel supply to the motor). Fuel related misfires can be caused by many different things such as low fuel pressure, faulty or dirty fuel injectors, a faulty O2 sensor, a dirty or failing mass air-flow sensor, a faulty or dirty idle air control valve or a vacuum or intake leak. When the fuel supplied to the combustion chamber is insufficient, this results in an ignition (spark) that is igniting a less than balanced load of fuel and air. This results in a misfire or an explosion in the cylinder that is much less powerful than the other cylinders. This creates a loss of power that resonates throughout the motor additionally causing other problems with ignition and fuel timing. Due to the number of different things that may cause an engine misfire, the quickest and easiest way to diagnose this type of problem is to hook the vehicle up to a scanning tool which will download any potential fault codes that may have registered in the vehicle’s computer as a result of the poor running condition. I would recommend having an expert from YourMechanic come to your location to diagnose your misfiring problem.
How to Identify and Fix Common car Problems ?
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From the spark plugs to the ignition coils, many different things can cause an engine to misfire. The most common causes of misfires are worn, improperly installed, and mishandled spark plugs, malfunctioning ignition coils, carbon tracking, faulty spark plug wires and vacuum leaks.
Worn and old spark plugs, spark plug wires, and ignition coils are common causes of random misfires. Replacing worn and old parts is part of regular maintenance for any car and should be done if needed (hopefully proactively to avoid misfires). After replacing the faulty plugs, wires and or coils, recheck for misfires.
Power is generated by pistons that move up and down while fuel is ignited at very specific times. A misfire typically occurs when the timing of this ignition is off. GMC Sierra 1500 P0300 indicates that two or more cylinders are experiencing misfires.
Battery issues, including the battery being dead or the terminals getting corroded, are the most common cause of this issue, and the first thing most mechanics will look at. Blown fuses and relays can cause this problem, too.
A clogged or failed exhaust gas recirculation or crankcase ventilation valve or faulty oxygen sensor can send the wrong signals to the computer and cause misfires.
Engine misfires can be caused by a list of faults, but there are a few suspects that occur more than others. The primary villains are simple – spark or fuel – usually manifesting in spark plugs, plug wires, the coil(s) or the fuel-delivery system.
Can a bad O2 sensor cause a P0300 code? Yes. As it is one of the most vital inputs to your car`s computer for fuel control, a sensor failure can result in an incorrect air/fuel ratio. In addition, it can lead to engine misfiring and set code P0300.
If the P0300 trouble code still persists, there could be a problem with the PCM. This may require replacing or reprogramming.
If the car cranks when you turn the key, but the engine won`t start, it could be because fuel isn`t getting to the engine. One potential reason for this could be dirty fuel injectors. Over time, the fuel injector nozzles can become clogged with rust, corrosion or debris.
If you don`t hear clicking when you start the engine, the problem may be a dead battery. If you hear clicking, but the engine doesn`t crank, the starter might not be getting enough electricity. Using your owner`s manual and a voltmeter, you should be able to test functionality.
A Bad Crankshaft Position Sensor
The crankshaft position sensor monitors the position and rotational speeds of the crankshaft. Without the crank sensor, the engine control module (ECM) wouldn`t know when to fire the fuel injectors and ignite the spark plugs.
On modern auto-start/auto-stop engines, the camshaft position sensor determines which cylinder is in its power stroke relative to the crankshaft position, delivering fuel and spark to start the engine when you step on the accelerator.
Misfires don`t simply go away – they need to be addressed immediately. Even if they don`t get worse, they certainly won`t get any better unless you take the car to a mechanic.
If left untreated, a cylinder misfire can lead to significant engine damage. Worse, if you experience a bad misfire while driving, it could result in an accident. This is why it`s important to treat engine misfires as soon as you detect them.
Can a bad O2 sensor cause a P0300 code? Yes. As it is one of the most vital inputs to your car`s computer for fuel control, a sensor failure can result in an incorrect air/fuel ratio. In addition, it can lead to engine misfiring and set code P0300.
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1999 gmc pickup, acts like it is not firing on all cylinders randomly
ANSWER : Engine misfires can be caused by many different problems and are generally caused by either a spark or fuel issue or in some cases, a combination of both. Spark related problems generally will result from things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition modules not working properly. When the misfire results from a fuel related issue, this is commonly related to a lean fuel condition (lack of sufficient fuel supply to the motor). Fuel related misfires can be caused by many different things such as low fuel pressure, faulty or dirty fuel injectors, a faulty O2 sensor, a dirty or failing mass air-flow sensor, a faulty or dirty idle air control valve or a vacuum or intake leak. When the fuel supplied to the combustion chamber is insufficient, this results in an ignition (spark) that is igniting a less than balanced load of fuel and air. This results in a misfire or an explosion in the cylinder that is much less powerful than the other cylinders. This creates a loss of power that resonates throughout the motor additionally causing other problems with ignition and fuel timing. Due to the number of different things that may cause an engine misfire, the quickest and easiest way to diagnose this type of problem is to hook the vehicle up to a scanning tool which will download any potential fault codes that may have registered in the vehicle’s computer as a result of the poor running condition. I would recommend having an expert from YourMechanic come to your location to diagnose your misfiring problem.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
went from starting quick to running like crap and sound like crap also has a small back fire noise like say B with ur lips silnt
ANSWER : Hello there. If the fuel tank is contaminated with debris, it should be either replaced or completely cleaned out. However, the problem with older fuel cells is they are metal, and likely have a lot of rust in the fuel cell; which will contaminate the fuel and lead to the "running like crap" issues. It is also possible that you have an exhaust leak which can create the same type of sound and backfiring problems.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
I just bought a new battery and i try to start it..it acts like it wants to start but its like theres no gas for it to stHey so ca
ANSWER : Hi There,
This may be related to many different possibilities, some of which may be related to a lack of spark and some of which may be related to a fuel delivery problem or a combination of both. Things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition module are all components that may cause the motor to not produce the spark needed to ignite the fuel in the motor.
This may be related to many different possibilities, some of which may be related to a lack of spark and some of which may be related to a fuel delivery problem or a combination of both. Things like ignition coils, crankshaft position sensor, spark plugs, spark plug wires or ignition module are all components that may cause the motor to not produce the spark needed to ignite the fuel in the motor.
In the case of a fuel delivery problem, this may be related to low fuel pressure, faulty or dirty fuel injectors, a faulty or dirty idle air control valve (this relays information about air intake to the computer which makes fuel adjustments), or potentially a faulty fuel pressure regulator or fuel pump. Fuel delivery problems will typically not allow the proper amount of fuel to be delivered to the cylinders which results in a lean fuel condition which can cause backfiring or simply cause the motor not to start as a result of fuel starvation. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
What is the main reason for a random misfire on Audi A6 2002 3.0
ANSWER : Hello, thank you for writing in. Without the codes that are present it is hard to narrow down the possibilities for you. Coil packs and fuel supply are going to be towards the top of the list. You should start by checking for recalls on the vehicle, as the coil packs on your vehicle may have been included in a factory recall. This means if they have not been replaced on the vehicle yet, and the coils are still factory, that the manufacturer will replace them for free. This can be done online with the VIN. Otherwise, electrical testing on the coils and fuel injectors needs to be done to verify if one of them is to blame. For more help with diagnostics or repair, contact our service department to schedule an appointment.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
#6 cylinder misfire. 1999 Ford Explorer
ANSWER : Hi there – unfortunately, pulling the plug on cylinder 6 is necessary for the next level of misfire diagnosis: is there actually spark at the plug while running? What is the compression on that cylinder (and any other – are they within 10% of each other)? Is that plug brown or black, or wet with fuel – signifying a leaking injector? You can get to a precise answer, but it will require a bit more effort. I would recommend an engine misfire inspection](https://www.yourmechanic.com/services/engine-is-misfiring-inspection) 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.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
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.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
Transmission is not responding when I put it in gear. All gears act like neutral.
ANSWER : Hi and thanks for contacting YourMechanic. It sounds like the pump pressure switch is overloading and causing a mass dump. Check the wiring harness to the transmission and see if there is power to the harness. If there is power, then check the pins on the transmission for continuity and see if any of the pins are really high. I recommend replacing the pump pressure switch in the transmission.
If you need further assistance diagnosing your vehicle, then seek out a professional, such as one from YourMechanic, to help you determine what is wrong with your transmission and replace the transmission oil pressure switch if needed.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
1983 toyota corolla 69k miles on it and when I’m driving it acts like it wont take any gas.
ANSWER : If the exhaust smells like gasoline, the fuel mixture is either way too rich or you have a weak ignition system that is not burning the fuel efficiently. You can pull spark plugs out to check them and if they are wet or black they may be fouled and this can cause very rough running, misfires and stalling. Consider hiring an experienced technician like one from YourMechanic who can come out for a closer inspection of the vehicle in order to run a few tests and offer a more personal diagnosis of your stalling and drivability concerns.
Read Full Q/A … : 1999 gmc pickup, acts like it is not firing on all cylinders randomly
