EMB-145 F/O reported that the crew could not control the pressurization system and asked ATC for priority handling.

Narrative

During a pre-flight review of the aircraft log book; we noticed that the aircraft had previous pressurization issues for the past four days. Maintenance actions were taken; such as replacing a digital controller. The Captain (PF) and I (PM) discussed the possible pressurization issues that may arise in flight; given the trend. We noted that a previous crew had a cabin altitude of 10;000 ft while flying at 12;000 ft which was significant due to our filed altitude of FL 320. Once we began the flight the pressurization appeared normal and did not catch my attention as pilot monitoring. At approximately FL 280 I began to notice a rapid increase in cabin altitude to 8;200 ft. and mentioned it to my captain. No EICAS messages were present. He transferred control of the aircraft and radios to me and began the appropriate QRH procedure. We leveled off before FL320 and descended to FL300; with the cabin alt increasing at a rate of 50-450fpm. The captain progressed through the QRH and utilized manual control to successfully bring the cabin alt from 9800ft and climbing; down to a stable 8100ft.; which was still an amber indication.Incremental adjustments to attempt to maintain 8000ft or less resulted in the control knob coming to its stop with no further adjustment possible. The QRH called for a cabin alt in the mid 5000ft range; the exact value I cannot recall. The captain proposed declaring once at 8800ft to 8900ft due to the rate it was increasing again and our lack of any further manual control. We agreed it was best to prepare for a descent before it became critical and to avoid panic amongst passengers if masks dropped; given that 9800ft had previously been seen in AUTO mode. Once the cabin alt. reached 8800-8900ft; I requested an immediate descent to 10;000ft and we conducted the emergency descent procedure per the QRH. Once complete the cabin initially stabilized to 7000ft and then 300-600ft while at level 10;000ft. It was able to be adjusted further in manual mode while descending lower. We kept an eye on fuel. We landed successfully and the remainder of the flight was uneventful.Cause: The incomplete repair and troubleshooting of the aircraft's pressurization system over the previous four days.Suggestion: Further troubleshooting and operational function checks could have been taken after the previous maintenance actions were taken. The trend of the same issue for several days with various repair attempts hints at a different root cause of the defect. Writing up our event as an 'AUTO pressurization fail' also does a disservice to those troubleshooting and those flying it. Even in manual mode it was not within the prescribed parameters; suggesting an outflow valve issue instead of an automatic controller issue.