Why is my truck running rough. 2000 Chevrolet S10

My truck had been running ruff for a year even after a tune up so I cut the converter off hoping that would work but it didn't…the fuel pump is working so what do you think…whatever made it stop was making it run terrible

My car has 254000 miles.
My car has an automatic transmission.

Experienced mechanics share their insights in answering this question :
Hello. Rough running can be caused by a number of things. To determine where the issue is I would usually start by scanning the computer for codes. This would help me determine if the issue is at a particular cylinder. If there are no codes then I would do a cylinder balance test to see which cylinders are acting up. Most of the time this engine has problems with the fuel injection unit. This is located inside of the intake manifold. Then unit becomes clogged and restricted and causes multiple misfires. In some cases the unit can be professionally cleaned, but in other cases it needs to be replaced. I will usually do a compression test also on this engine to make sure that it is good internally. If you want to have this problem figured out, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the engine is running rough] https://www.yourmechanic.com/services/car-idle-is-rough-inspection

How to Identify and Fix Common car Problems ?

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

The most common reasons a Chevrolet S10 has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
Malfunctioning Throttle: A malfunctioning throttle system can cause both a high or low idle as well as an engine stall. A dirty air intake or cracked air intake tube is often the culprit. Computer Malfunction: If the powertrain control module is malfunctioning, idle speed may be affected.
A rough idle without any codes could be caused by various factors, such as vacuum leaks, a dirty throttle body, a malfunctioning idle air control valve, clogged fuel injectors, clogged air filters, poor quality fuel, or even a blown a fuse.
What could the problem be? There are a range of reasons why your car is juddering when you accelerate. Your vehicle could have dirty fuel injectors, a damaged fuel pump, a blocked catalytic converter, a faulty mass airflow sensor, broken spark plugs, or even an accumulation of moisture.
Dirty/Faulty Fuel Injectors – Fuel injection systems play an essential role in starting your vehicle. The system injects fuel and air into the cylinders. If clogged or gummed up, the injectors don`t provide the right mix of fuel and air, resulting in a rough idle or slow acceleration.
Low or high fuel pressure from a dirty fuel filter, defective fuel pump, clogged fuel tank strainer, bad fuel regulator or dirty/clogged fuel injectors can cause rough idling. Try replacing the fuel filter and add fuel injector cleaning treatment to your fuel tank to clean and hopefully unclog your injectors.
The most common problem is a faulty fuse. In modern vehicles, engine idle speed is most often controlled by the idle air control (IAC) motor. This can be impacted by bad fuses in many different electronic systems in your car. Next, your high idling could be caused by a computer malfunction.
Engine Misfires

Perhaps the single most common cause of rough idle comes in the form of a misfiring engine. As you may know, any automotive engine contains multiple cylinders. Each of these cylinders contributes to powering your car by combusting a mixture of gasoline and air.

How to fix it? Cleaning or replacing the fuel filter and adding a fuel injector cleaning treatment to the fuel tank should take care of clogged fuel injectors. If the rough idle persists, it`s time to take your car to an auto repair shop.
While some cases are less severe than others, a rough idle is usually identifiable by a shaking and bouncing sensation in the vehicle. You may also notice odd sounds, as well as inconsistent RPM counts. Normally, a vehicle should have a smooth and consistent RPM rate of around 1,000.
Dirty fuel injectors are among the most common reasons for why an accelerator becomes jerky. The dirty injector leads to your car losing power when you attempt to accelerate while at a stop and when you try to drive at a consistent speed. This is the result of an engine misfire.
Trouble accelerating can come from a few different engine issues. These include, but are not limited to, dirty fuel injectors, low fuel pressure, and restricted airflow. A problem with the mass airflow sensor, throttle position sensor, or engine speed sensor can also cause a car to have difficulty picking up speed.
The most common cause of engine sputtering are issues with the fuel system. These can range from bad fuel filters, fuel pump issues, or fuel injector issues.
If your car hesitates when accelerating at low speed, you likely have a lean air-to-fuel mixture—meaning the gas getting to your engine doesn`t have the correct mix of fuel and air. in your car. can cause an improper air-to-fuel ratio if even one of them isn`t working right.
Fuel injectors may become dirty over time and not be able to provide as much fuel to the cylinder as is needed. Dirty fuel injectors may cause the engine to run lean which will in turn, cause hesitation when accelerating.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

The truck intermittently, has a very rough idle, and runs rough,usually after warming up.
ANSWER : Hello. This can be caused by a number of different things. If this occurred right after you had gotten fuel then I would start by testing the fuel pressure. I would do this when the vehicle starts running poorly. It is possible that the bad fuel contaminated the fuel pump and it is not putting out the right pressure. If the fuel pressure is fine then I would check the other sensors readings with a scan tool. One other common thing that I have seen on this engine is a leaking intake manifold gasket. It starts leaking on the bottom side and that leak causes the MAF and MAP to not read correctly which causes it to run like this. If you would like to have this rough running condition looked at, consider having a YourMechanic certified techniciancan come to your home or office to diagnose why it is running rough.

Vehicle started running rough while driving. Now running/idling rough running rich.
ANSWER : Hello. From the symptoms you describe, it would appear that your vehicle is having issues with the oxygen sensors. P0172 is the code for bank 1 being too rich. This can be caused by a wide variety of issues. The other two codes are for the sensors on bank 2, having excessively high voltage.

This may be due to the rich condition, faulty oxygen sensors, or faulty wiring. The black smoke and soot is a result of excessive fuel that is not being properly burned, and exiting the tailpipe as smoke. A few common causes for these symptoms are a bad fuel pump, fuel pressure regulator, or engine management sensor. As engine management systems can sometimes be difficult to diagnose, I would recommend having the rough idling issue inspected by a professional technician.

Why is my truck running rough. 2000 Chevrolet S10
ANSWER : Hello. Rough running can be caused by a number of things. To determine where the issue is I would usually start by scanning the computer for codes. This would help me determine if the issue is at a particular cylinder. If there are no codes then I would do a cylinder balance test to see which cylinders are acting up. Most of the time this engine has problems with the fuel injection unit. This is located inside of the intake manifold. Then unit becomes clogged and restricted and causes multiple misfires. In some cases the unit can be professionally cleaned, but in other cases it needs to be replaced. I will usually do a compression test also on this engine to make sure that it is good internally. If you want to have this problem figured out, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the engine is running rough] https://www.yourmechanic.com/services/car-idle-is-rough-inspection

01 mustang v6 running rough at idle and drive. Please help. Replaced a bunch, still can’t figure out issue.
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.

I changed the fuel pump and truck ran great for 3 days. Now after 3 days, the truck dies. It will start running for a few minutes, then dies like before.
ANSWER : Hi there, thanks for writing in. I’d be happy to help. It sounds like you should disconnect the connector to the fuel pump and inspect it for any signs of getting hot. The female connections may be too loose on the fuel pump and lose contact after running and getting hot. If there are indeed any signs of problems, then I’d suggest replacing connector and adding dielectric lube to pins before installation. This should solve the problem, but if you continue to experience issues, feel free to reach out to us for help again.

Engine in my truck is running rough, maybe oil problem?
ANSWER : Your problems are a common complaint voiced by other owners. You will need to have your engine checked for possible lifters that have collapsed and could damage the cam shaft in the engine. Some owners have changed oil types to a different synthetic brand and this has helped alleviate the conditions but did not fix problem. I would recommend contacting YourMechanic to get the noise verified and diagnosed to prevent possible damage or major engine failure. You said you use a lot of oil and have run low on oil before. You should check for possible piston rings causing this. Diagnosing the noise should be your top priority, and once the issue is identified, make the decision to overhaul or replace the engine with a remanufactured one. Proper diagnostics are the key to prevent engine damage.

When the truck is rolling with clutch in the truck will idle rough and sometimes dies.
ANSWER : This is a common symptom of the idle air control valve failing. This unit monitors the air intake as it is mixed with fuel prior to entering the motor. When this fails, this will cause a rough idle at low RPM’s. I would recommend having an expert from YourMechanic come to your home to diagnose the rough idle firsthand for an accurate repair.

I have a 1998 ford ranger(AT) its shifting roughly, when i come to a stop, the truck wants to keep going, and as a result, the truck stalls out.
ANSWER : The torque converter clutch is not releasing as the transmission is shifting. Try pulling the fuse to the torque converter labeled as TCC and see if the symptoms change. If the vehicle stops acting up, then the torque converter clutch solenoid is active and not releasing. If the symptoms are the same, then the torque converter clutch is melted and needs replaced (torque converter replacement). If you need further assistance with your transmission shifting hash and stalling, then seek out a professional, such as one from Your Mechanic, to help you.