So I have been misinformed, thank you for correcting that.

When you say EI module, can I safely assume you refer to what I've always called the ignition module beneath the coil packs? We replaced that module when I bought the car due to lack of spark on two cylinders. I had one from an SOHC engine laying around from work on my SL1, and my dad assumed they would be nearly identical despite this being a DOHC engine. Could this be the culprit?

When I bought this wagon, we had to overhaul the engine to fix a lack of compression on cylinder 3 caused by overheated and warped valves. When we did this, we replaced all four spark plugs due various issues each of the former ones had, so I doubt those would be the culprit. I also doubt remaining ice or water as we had two days of nearly 40 degree weather and I drove the car at least 30 miles each day, as well as 60 miles the following day.

The efficiency of this car is definitely not what I expected too. I use an app on my phone to keep a running tally of fuel efficiency and maintenance costs, and looking back, I've gotten mostly low 30's and high 20's for mileage. Definitely not what I expected, especially considering my SL1 never got below 30 unless something was wrong with the engine.