Vehicle “Shivers”/Shudders” and RPMs pulse

[Motorcity muscle]

What was his reasoning? I thought Shudder Fixx was simply a lubricant to reduce friction.

He said the new fluid has everything in it that’s needed

 

[Dsurkamp]

I put new spark plugs, also checked the gap, on our 2018 Expedtion Eco Boost when going to Florida this year and around 70 when you punched the gas it would shake but if I eased the gas it was fine. Well bought new spark plugs again once I got back from the trip and just put them on. It stopped my issue.