Thanks for the comments MPGomatic!
I am currently using Castrol GTX 5W-30 conventional oil. I figured if I switched to full synthetic it may blow by the seals since the vehicle has such high mileage. As for the fuel system, I may have to do that too. A new fuel filter, fuel pump sock, and cleaned injectors will be added to my "To Do" list. As for tires, I do not have LRR tires.
One month progress update:
I did a recent tune up changing spark plugs, oil, and oil filter. When I pulled the spark plugs I noticed they were not the same plugs that were recommended by the Honda HX user manual. The plugs that were in the car were actually NGK ZFR5F-11's. So I swapped them out with the correct ones, NGK V-Power ZFR4F-11's which the HX calls for. Was there a difference? YES!!!
I noticed the car engaged into lean burn MUCH easier in 4th and 5th gears. Idle rpm is much better and slightly lower by 100-150 given rpm's (idle was originally around 790-850 rpm according to the Scangauge, with water temp @ 185F). My mpg went up to 37 to 40 mpg's on a given tank, that is with air conditioning on (toggled off during uphill climbs and accelerating from stops) and tire pressure at 42 psi.
I will probably do the EGR chamber clean up soon and see if that makes any additional difference (ordered new egr chamber gasket and egr valve gasket from Majestic Honda earlier today). My upper grill block is in the making and will be put on soon since the weather temps are starting to cool down a bit here in Texas. I should be able to run the car with the AC off more often now.
I've also consider maybe adding some hood hinge spacers and longer bolts to see if it will help the air flow transition from the hood/windshield while reducing under the hood engine temps (an idea taken from the Honda drag racing world that my buddy mentioned to me). I figured it would be worth a shot instead of removing the wipers or modifying the hood itself. I should be able to watch where the rain droplets flow over the windshield while driving confirming if it works maybe?
As for the lower grill block, I have a spare bumper that I may use as a template to make a block that will accommodate for fog lights and adjustability of air flow to the radiator via ducting and an additional puller fan.
As for the CX transmission I picked up, I've cleaned it up, resurfaced the CX flywheel, and is ready to be installed once my new clutch gets here. I'll weigh the HX and CX flywheels to see if there is a difference.
I have also done other normal maintenance such as full brake fluid flush, clutch fluid flush, power steering fluid flush. Still needs a coolant flush and transmission flush, but I will have the CX transmission in with fresh fluid.
Minimal gains so far, but any progress is better than no progress!
