I have a 97’ Ford Windstar 3.8L (185k miles) with the original engine and transmission. This van has allowed me to keep upgrading/updating my HT for several years now, since it’s paid for, so I take very good care of it. The van still runs surprisingly well (considering it’s a Windstar and it’s mileage) with the exception of the number 2 cylinder, which is losing compression and fouling plugs about every 5-10k miles. A friend who is a shade tree mechanic suggested that I just keep popping a new plug in (#2) and ride it until she falls apart. I was considering trying a “High Mileage” oil to help with the compression loss on #2. Would it be worth the extra expense? Also, when the van was new I used 5W-30, around 100k I started using 10W-30 weight oil. Should I stick with 10W-30?