[ludicrist]

The only way these additive products will show any improvement is if there is a problem with contaminants in the fuel system . I recently purchased a can of MAF cleaner from CRC right on the can it claims 6-10 hp from this is it a gain no but you may have lost it from the OIL on the K&N getting on the MAF . [ you guys that are running K&N or any oiled filter should be cleaning the MAF every 10-12k a dirty MAF can cause erratic shifting and reduce performance.] See I'm not hijacking the thread you guys are looking for better MPG and I'm telling you how you can actually get it . I only tune about 25 GM products a week and 50% get a Fuel economy tune with a slight bump in HP .