As far as the PEA cleaners go, I would use a product and then reset my cars fuel computer, note avg mpg for that tank of fuel and subsequent tankfulls, I would see an increase of about .5 avg, this was done every 5000 miles. Also noted was drivability performance, after about 10 gallons of treated fuel used, the engine becomes noticably more responsive, even the vibrations during acceleration change, during the accrued 5000 miles the MPG would drop back to the starting point and develop a slight decrease in performance, I would repeat the whole process for each of the brands and do it more than once, the cleaners just restore MPG & performance. I also have easy access to the front bank of spark plugs, remove plug and using a long flexable LED light I can see into the cylinder, it does become noticably cleaner, not perfect, but it looks better. Lucas did nothing noticable for my car. I like Redline Products.
Now onto the UCL, once again fuel computer is used and reset for each tank of fuel, slight increase in MPG is noted, .5 avg along with smoother feel during acceleration and better idle quality, MMO worked fairly well but at a reduced dosage, 4oz to 6oz per 20 gal, TCW3 created a smooth running engine but performance dropped off, I would notice a lack of response during light throttle, I could drive through it and get the rpm's up, even at a reduced dosage, same thing. Lucas did nothing. Now the gem of the fuel adds FP-60, this was noticable right off, very smooth acceleration, very stable idle, increase in performace, better throttle response and it's also a cleaner, so from here on out looks like i'm going to be a FP-60 user. Also to keep in mind, most cars today have a returnless fuel system, so it takes me ".4 gallons used" of fuel before I notice any changes with the UCL, it seems it takes .4 gallon of fuel to make it through the fuel lines and filter to the fuel rail and into the injectors.
