Need help / advice. I have a 2004 4X4 Lariat Supercrew with 16K miles. I put the Flowmaster Force II Exhaust System (Single Side Exit) on my pickup at 14K miles and have noticed a decrease in gas mileage and performance since the system was added. The performance decrease is mostly at low RPMs (throttle lag was magnified). Vehicle was built in 08/04. I have not have the PCM flashed and do not know if that may help. Only other modification is K&N drop-in.

Are there any solutions? Anybody else have the same system with the same result?

 

I had a Flowmaster 40 SIDO installed at about 300 miles and I have no doubt that it took away some lowend torque, but I did not notice a gas mileage dip. I put in a K & N dropin at about this time, don't think it does much but save filter money. I had to have the reflash at about 2600 miles for the hesitation and lag, and it made a world of difference. Then, at about 32,000, I added the Edge. This woke my truck up greatly. I would hate to give up my tuner. I think Flowmaster does take away some torque, but i love the sound, and that was what I was after. Get the Edge or a Troyer Xcal2 and your problems will go away.