Replaced all ignition componets and still missfires and poor power through out rpm range

Inspect Clutch and Belt: Check the clutch assembly and the belt that drives the compactor. Look for signs of wear, damage, or misalignment. A worn-out clutch or a loose belt can cause the clutch to overheat and the engine not to rev up properly. If you find any issues, consider replacing the clutch or realigning the belt. Check Engine RPM Sensor: The engine's RPM sensor is crucial for the proper operation of the compactor. If the sensor is faulty or misaligned, it may not provide accurate RPM readings to the engine control system. This can lead to performance issues. Inspect the RPM sensor and its connections to ensure they are clean and secure. Inspect Air Filter and Fuel Filter: A clogged or dirty air filter can restrict airflow to the engine, affecting RPM and overall performance. Similarly, a clogged fuel filter can lead to fuel delivery problems, resulting in poor engine performance. Check both filters and replace them if necessary. Fuel System Inspection: Examine the fuel system, including the fuel pump and fuel lines, for any blockages, leaks, or malfunctions. Insufficient fuel supply can cause the engine to struggle with RPM. Throttle Cable and Linkage: Check the throttle cable and linkage to ensure they are not sticking or binding. A faulty throttle mechanism can prevent the engine from reaching the correct RPM levels. Engine Timing and Compression: If the engine timing is off or if there are compression issues, it can lead to poor performance and overheating of the clutch. Perform a compression test and check the engine's timing to ensure they are within the manufacturer's specifications. Inspect Vibration Isolators: The BPU 4045 compactor operates under heavy vibrations, and these vibrations can affect various components' alignment. Check the vibr
Check clutches and belts: Check clutch assembly and belt connecting compactor. Look for signs of wear, damage, or misalignment. A worn clutch or loose belt can cause the clutch to overheat and result in poor engine performance. If you experience any problems, consider replacing the clutch or resetting the belt. Check engine rpm sensor: The engine rpm sensor is required for proper compressor operation. If the sensor is faulty or incorrect, the engine control system may not be able to give an accurate RPM reading. This can cause performance issues. Check the RPM sensor and its connectors for cleanliness and tightness. Check air filters and fuel filters: Clogged or dirty air filters can restrict airflow to the engine, affecting overall rpm and performance. Similarly, clogged fuel filters can cause fuel supply problems, resulting in poor engine performance. Check both filters and replace if necessary. Fuel System Inspection: Inspect the fuel system, including the fuel pump and fuel lines, for blockages, leaks, or malfunctions. Insufficient fuel can cause engine rpm to drop. Throttle Cable and Linkage: Inspect the throttle cable and linkage for sticking or binding. A damaged throttle mechanism can prevent the engine from reaching the correct RPM range. Engine timing and pressure: If the engine timing is off or there are pressure problems, it can cause poor performance and overheating of the clutch Perform a pressure test and check the engine timing to ensure it is within the manufacturer's specification. Monitor vibration isolators: The BPU 4045 compressor operates under heavy vibration, and this vibration can affect the compatibility of components. Look at how it shakes

First, what are you working on? Some cars (chevys) have ignition modules with a low rpm section and a high rpm section, so they may start and idle fine but act up at speed. Bad coolant temp sensor can act like choke is stuck on (or off as well). Weak coil can cause this. Clogged cat converter or muffler can do this. Weak fuel pump or clogged filter also.

May be a fuel or ignition issue . The EGR stuck open only hurts it at idle and tip in off idle acceleration .

Sounds like you may have some ignition/O2 sensor or even cat issues , as these codes range from missfire to lean bank problems how many miles are on it? Whenwas the last tune up performed?

misfires can come from faulty injectors, low fuel pressure in the manifold. timing , blocked exhaust. faulty o2 sensor, leaking inlet manifold gaskets, faulty valves (burnt) It is not always plugs and leads. Have a fault code reading done.

the code p 4044 refers to exhaust gas recirculation range /performance--reading above or below the specified range
could be a problem valve or solenoid or wiring
the remark about the cat converter is valid as it indicates that when under load the cat converter is blocking the exhaust
this occurs when the honeycomb internals cracks and the bits block the exhaust exit under high gas flows ( from your use description)
you can get replacement cat converters that use flange fittings and they are therefore cheaper when needing replacing
cat converters crack when running hot and are then immersed in extreme cold ( snow , running ice water)when driving

REPLACE DISTRIBUTOR CAP AND ROTOR REPLACE SPARK PLUGS AND WIRES IF NOT BEEN CHANGED IN LONG PERIOD OF TIME.CHECK IGNITION TIMING.CHANGE AIR FILTER CLEAN FUEL INJECTORS.IF ENGINE STILL MISFIRE IGNITION COIL IS WEAK OR YOU HAVE LOW CYLINDER COMPRESSION.

well you could have had a cat converter go bad before thats possible,either you now have a piece of the old broken cat stuck in the exhuast pipe,or you have what i think is a bad ignition module/coil pack and spark plugs causing a major misfire causing it to over heat and have no power,,,or its out of timing causing the same issue,,its odd it has no codes,no ses light,if its a bad coil its got a ses,,these are just a few ideas its too hard to tell without seeing the car

1 of 4 coils you have, dont keep doing this cos now you need a new cat as well as the coils to buy get the coils first tho'

Sounds like the cat is clogged. Replace it. This is caused by bad gas or just because it got old. Also, have a look at ignition wires. Timing belts either are functioning or broken. They don't sound like anything. If you are at a recommended replacement point...do it. It's much cheaper than waiting for it to break. Engine damage could result upon breakage.