Yes and no… Lucas brand fuel injector cleaner and seafoam are the only thing keeping my dad’s 2001 cherokee on the road, see in 1999 when chrysler re-designed the head in the 4.0 the put the injectors a little to close the the exhaust manifold…
Now see this becomes a problem because when you shut the engine off without letting it cool the heat from the exhaust will crystallize the fuel within the injectors, about once a year my dads jeep gets a random misfire on some random cylinder, with a little lucas fuel treatment, the problem goes away…
The problem of course is that this can break sentiment from the bottom of the tank that will get gunked up in the fuel filter, but this is still the best “fix” for his problem…
Also as stated on jay leno’s garage using the exact Lucas brand injector cleaner can help save old cars that were intended to run with leaded fuel as it also acts a lubricant, my uncle uses it about every other tank or so in his classic cars…
Other than for these 2 problems, as pointed out on fifth gear, fuel additives are useless..