Do not use Valvoline SynPower fuel cleaner.
 

I tried some not to long and I have been very disappointed with the results so far. Basically the story goes like this, I top off my car with some 93 octane gas and drive to work. On the way to work my engine was reading zero on knock retard. That night I add a bottle of the above mentioned fuel system treatment and since that day my engine now has to pull it's timing back under any throttle load. Under a heavy throttle load the engine is having to pull back its timing between 4 and 8 degrees. I will never use Valvoline products again because of this shitty fuel cleaner. I'm still way over 3/4 of a tank so I might try adding some octane booster to see if that helps.

I'd like to see what some of the other brands do

I've used Lucas Fuel Injector Cleaner in the LS1, I notice that the vehicle runs a lot smoother. Gas mileage got slightly better, but the engine also was more responsive.

I keep forgetting to pickup the booster. :mad: I did a heavy throttle run today and the scan master recorded an 02 reading of 925 milivolts with a knock retard of 5.0. :eek: I need to go into town later so I guess I will have to break down and use one of my 104+ bottles and see if that helps. As for fuel cleaners I do agree Lucas does work good but I would never buy it because of the fact I hate the brand itself. :lolsign:

lucas is known snake oil on the oil side, so I have a hard time with anything they make.Once you get it going again try seafoam and see what it does, it may be the cleaner itself doesn't burn

Same way I feel, Lucas has built up a name and runs on that alone. And the fact you pay over $8 bottle for the cheap stuff is just nuts.

thanks for the warning

Forgot to mention that octane boosters will foul your spark plugs. I pulled mine out at 20,000 miles, to see them fouled. You are really better off just doing a 100 octane mix with whatever premium fuel is, in your state.

I've never had a problem with octane boosters,I did see some ac delco plugs foul with premium more than once (the rapid fires were teh worst for it)