1996 Ford Ranger P1443 and P1000 Codes: Solenoid, Sensor Issues and Drive Cycle Explanation

My 1996 Ford Ranger is showing both P1443 and P1000 diagnostic codes. I've already replaced the purge solenoid and evaporative emission sensor, but the issue persists. The original purge solenoid was stuck open—after replacement, the check engine light went off for about two months before returning. The sensor was then replaced; however, I was given a Standard Products CP416 model instead of the discontinued CP509. The CP416 does not perform as expected—it fails to maintain vacuum resistance and causes the CEL to come on quickly. I switched to a Wells brand PV342 sensor, which is an exact replacement for the CP509. After installation, I cleared the codes using my scanner, but the scanner LED turns yellow and remains that way until the check engine light reactivates after about one week. This suggests the drive cycle may not be fully completed. The purge solenoid appears to function correctly—it clicks when operated above idle speed. However, during testing with a vacuum gauge, I observed no vacuum at idle but consistent vacuum above idle when the hose is disconnected from the canister. I've also found that the new sensor does not hold vacuum and bleeds off quickly—similarly, the old sensor leaked slowly. This indicates the sensor may be defective or improperly installed. The solenoid itself previously failed to maintain vacuum; after cleaning, it now holds vacuum properly. After researching Ranger forums, I've learned this is a common issue across 1995–1997 Ford Rangers. My current theory is that the vehicle may not be completing the full drive cycle required for the system to fully test and clear the P1443 code. However, given the vacuum performance issues with both solenoid and sensor components, I suspect a deeper issue—such as charcoal canister degradation or internal blockage. I have also found that loose charcoal fragments from a deteriorated foam filter may enter the purge solenoid, causing it to remain open. This is consistent with my experience where the system would go into a stuck-open state after initial repairs. I am now planning to test the new sensor with a vacuum pump to confirm its ability to hold vacuum under controlled conditions and will re-install the original sensor temporarily to verify if the code clears. If so, this may point to a faulty replacement part or an internal canister issue.