Misfire at hard thottle, rpms either dont go up when accelerating, or slowly drop as i accelerate

My grand prix has began to hesitate and misfire under hard throttle, im unsure as to why which is why im asking here. This is whats been fixed and whats new on the car:

Mass Airflow Sensor
Manifold Absolute Pressure Sensor
Spark Plugs- NGK TR6
Spark Plug Wires- MSD Street Fire 8mm
Ignition Coils- all 3 of them
Vacuum lines running to map sensor and supercharger bypass solenoid
Supercharger Bypass Solenoid
Supercharger Bypass Valve
Accelerator Pedal Sensor
Fuel Pump- Airtex E3700M

After all this it still acted strange so I removed the fuel injectors and manually cleaned them aswell, and rei

Experienced mechanics share their insights in answering this question :
Hi – check your vehicle’s fuel pressure when running, and under load. Your comment regarding "fuel trims …erratic" gets my attention. If the pressure is not correct, check the fuel pump relay (possible burned contacts) and fuel pressure regulator. If the pressure is correct, I would suspect the injectors need professional cleaning and testing – given your mileage. I would recommend having an Engine is Misfiring Inspection completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem, get an accurate assessment of damage and cost estimate for repairs.

How to Identify and Fix Common car Problems ?

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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.
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 common cause is a problem with the spark plugs or ignition system. Other potential causes include a blockage in the fuel line, a faulty oxygen sensor, or a problem with the mass air flow sensor. Vacuum leakages can also cause a delay in acceleration. A clogged air filter or low engine oil level can also be a cause.
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.
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.
Transmission Problems

Also, a faulty automatic transmission torque converter can cause poor acceleration from a stop. Some of the most common transmission-related problems that can lead to a loss of acceleration include: Internal automatic transmission failure.

Many supposed carburetor-related problems like low-speed hesitation can be traced to improper ignition timing.
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.
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.
Easy ways to get ride of throttle delay is by making sure you keep up with basic maintenance like change fluids, air filter, fuel filter, tire pressure which all help to improve speed, fuel economy. Making sure you have clean fuel filter will help improve fuel economy, speed, and rpm at various shift points.
When a throttle body is not functioning correctly, you`ll usually notice a distinctly poor or very low idle. If the problem is really severe, you might even begin stalling when coming to a stop or when the throttle is quickly pressed.
If you`re driving at freeway speeds and notice your engine sputter or jerk, you may have a failing fuel pump. This problem is caused when the fuel pump can`t deliver a smooth flow of fuel to the engine; periodically, your engine receives only air when it was expecting to receive fuel.
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.

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.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

Misfire at hard thottle, rpms either dont go up when accelerating, or slowly drop as i accelerate
ANSWER : Hi – check your vehicle’s fuel pressure when running, and under load. Your comment regarding "fuel trims …erratic" gets my attention. If the pressure is not correct, check the fuel pump relay (possible burned contacts) and fuel pressure regulator. If the pressure is correct, I would suspect the injectors need professional cleaning and testing – given your mileage. I would recommend having an Engine is Misfiring Inspection completed by a mobile, professional mechanic, such as one from YourMechanic, to diagnose this problem, get an accurate assessment of damage and cost estimate for repairs.

My car shifts gears just fine but it hardly wants to take off and the rpms go up very high but hardly accelerates. 1994 Honda Civic
ANSWER : Hello – I believe you have a severely slipping clutch. Either the clutch is worn out, or the clutch disc is contaminated with engine/transmission oil, and is slipping for that reason. If the clutch has not been replaced with your close to 300K miles, it is certainly time to replace the clutch. Unfortunately, that is not a service YourMechanic.com offers at this time. Thanks for thinking of us though!

RPMS rarely go past 3000 except pushing down hard on accelerator
ANSWER : Hi there. It’s highly likely that you have a clogged fuel filter or low fuel pressure. It’s also possible that the air filter is dirty and needs to be replaced. In some rare instances, an electrical gremlin with the ignition system can cause the engine to "govern" itself at a certain RPM. The best way to resolve this issue, and probably a good idea since you just purchased the vehicle is to change the fuel filter and air filter for starters. If the problem continues then you may need to have an acceleration diagnosis completed by one of our professional mobile mechanics.

Leaving stop light car runs high rpms 5000-6000 and doesn’t want to go over 20 mph 2009 Chevy Traverse
ANSWER : Hi there – first thing to check is the transmission fluid level – low fluid levels can cause lots of problems like this – your transmission is obviously slipping badly. If the fluid is at a correct level, and doesn’t smell burned, you may well have burned out clutches in the transmission, or solenoid or valve problems in the valve body of the transmission. The problem codes reviewed by your mechanic should have helped guide the diagnosis. I would recommend a 2nd opinion transmission 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.

When start out driving when accelerate does good to 2000 rpm and then when go to accelerate more it drops off and have to let off
ANSWER : Hello. From what you describe, it would appear that your vehicle is experiencing some sort of engine performance issues. Problems accelerating under load can be caused by many things. A few common causes are issues with the ignition, engine management, or fuel systems. If any components to those systems, such as an ignition coil, module, sensor, or fuel pump, have an issue, they can cause the engine to experience problems under load. If the Check Engine Light is on, I would recommend having the trouble codes scanned to see if that may shed some light on the issue. If the check engine light is not on, then the first thing I would do is test the vehicle’s fuel pressure, as fuel pressure issues can sometimes occur without the light coming on. A certified professional from YourMechanic can inspect the acceleration issue for you in person to pinpoint the appropriate repair.

Hard acceleration and hard braking when stop
ANSWER : You may be having a normal condition. When you accelerate hard, you are dumping a large amount of fuel into the engine and then stopping quick and shutting the throttle. You still have all that fuel in the engine and it has too much fuel for the engine to idle good for a few seconds. If you have a Check Engine Light or feel the idle is getting too low or it stalls, then you should have the system checked by a mechanic.

When I accelerate, my car hesitates, the rpms bounce, and sometimes i have a missfire flashing CEL
ANSWER : Hello and thank you for your question. With having your engine with bank 1 being lean (lack of fuel), the symptoms are showing that there is a problem with fuel delivery or excessive heat. If the EGR valve was to be stuck open, the engine will get more burnt fuel into the cylinders and cause them to heat up making the computer back off the fuel until needed.

The MAF sensor tells the computer how much air is coming in the engine. The MAP sensor tells the computer how much pressure is on the manifold. The throttle position sensor tells the computer where the throttle plate is located at.

If you are getting a code for bad connection between all of these sensors, then there is a bad ground connection or the harness to the vehicle is broken somewhere. The ground to the sensors are in the computer and the throttle pedal. So if the ground is the problem, then you would need to replace the computer or throttle pedal or both. Check all of the harness plugs to all of the sensors and use a digital volt meter to check for power to all the sensor harness connections using a paperclip. Then check all of the ground circuits with resistance. If you have some resistance but not a lot, then the circuits are okay. If you have no resistance, then the ground circuits are broken somewhere between the harness plugs and the computer or pedal. I would recommend having a professional diagnose the hesitation issue and move forward with appropriate repairs.

When I press the gas pedal the engine revs but the car doesn’t accelerate. Is this a throttle or transmission issue?
ANSWER : Hi there. From what you are saying it sounds like there is a failure in the throttle body. When the motor in the throttle body fails, the throttle plate will open and close causing the noise you are hearing. I usually monitor the movement of the throttle to see if this is what is occurring. I then scan the computer for codes to see what comes up. If there are not any codes then the sensors in the throttle body should be monitored to see what is going wrong. If you want to have this lack of throttle response checked, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair your throttle body issue.