I used the guaranteed "decarbonizer" from RCR for $6.00 on my Grand Wag. I failed inspection 2 years ago, passed this one WAY below standards (had the HC problem at idle).
1985 190D 2.2l Sold-to Brother-in-law
1996 Mustang 3.8l -"thinks it's a sports car"
1988 Grand Wagoneer - Sold (good home)
1995 Grand Cherokee Ltd -"What was I thinking??!!"