Ever since I've installed my header, I've been without a cat. Since the SES light has been on it seems like Gas consumption has been on the rise. I first attributed that to a heavy right foot...just wanting to feel that extra high rpm power...but it's still persisting. Could it be because of the SES light that I'm using more fuel? If so..I'm intersted in a high flow cat. Will that make the SES light go away? If so..what are some recommendations?

 

It is absoluetly normal-the DME is seeing no variation or change from the pre-cat & post cat oxygen sensors, causing the mixtures to richen out-thereby burning more gas. A small displacement motor need SOME exhaust backpressure that the cat provides, so without it the cylinders aren't scavenging al the unburned fuel out. Plus it screws with the flow chactoristics of the exhaust (see cylinder scavenging comment). My advise: Put the cat back in before you burn something up. Besides, you'll flunk emissions. The car was designed to run WITH a cat, and the performance gain you get is marginal at best. Try an '05 tranny-you'll lose the cruise control but the close ratios of the box really wake the car up. Cheers!