2005 ZX4 5 speed Manual opinions and recommendations

[Dillon92]

Ok so as the title says, 05 Focus ZX4, little over 200K miles. Car runs good for the most part. Used as my daily commuter too and from work. When I first got the car a year ago, I was told that the FUEL RAIL PRESSURE SENSOR was going out and that all it did to the car was lower the gas mileage. Low and behold, after driving it for a couple weeks, car dies on me while I'm out running errands. Go ahead and swap out the sensor for a new one and the car is back to running fine. Still have the occasional dips in power while cruising at the same speed, like on the highway, but no other major issues. Fast forward to now, engine light comes back on. After a few days of driving, engine light goes off by itself. Not sure if the computer system reset itself or what but after about another month, engine light comes back on. Scan for codes and I get P2004 and P2008. Haven't really been able to find much on either codes apart from the P2004 (Intake Manifold Runner Control Stuck Open Bank 1). I know I'm most likely going to have to take my car in to the shop to properly diagnose and fix that issue. But I'm also getting P2008 code (Intake Manifold Runner Control bank 1). Haven't been able to find much on that one apart from recommendations, which haven't been many. At this point I'm taking a chance and going to swap out the imrc solenoid for a new one. They only run about $150 bucks and it seems easy enough to swap out. From what I understand, if that doesn't fix the issue, then its definitely headed to the shop and hopefully doesn't break the bank. Now apart from the codes and dips in power when driving, when i start the car up on a cold start, the rpms shoot all the way up to 3000 for a few seconds then slowly idles back down. Then after driving the car for a bit and it gets fully warmed up, when i come to a complete stop, the car idles below 1000 rpms. Sometimes it drops down to 500 rpms at times. Most of the time it kind of bounces in-between 500 and 1000 rpms. Get worried that its going to die sometimes. Either way, I really need to get this figured out so i have a reliable vehicle. Any recommendations or advice would be greatly appreciated. Thanks in advance.