I'll apologize in advance for the newbie question, but I figured I'd get some good answers here.

My '04 is basically stock. Only performance mod is a Buschur intake. I've got a Defi boost gauge installed and at WOT I am only boosting about 16psi and tapering to about 14psi. I imagine that the recent heat has something to do with it. It's been right around 100* for the past couple weeks.

Is this just an obvious boost leak or what? Shouldn't I still be hitting close to 20psi even in the heat? If I build a homemade boost check tool, do I need to pull the bumper? Any other things I can look for?

Ok as for Fuel economy. I've typically been getting around 220-240 miles per tank since the car was new. That's been pretty consistent. I had the dealer do my 60K mile service about a month ago (since I'm still under my 100K mile warranty, hence the reason I'm still stock). Ever since the 60K mile service, I've only been getting about 170-190 miles per tank. That seems like a big loss. My driving style hasn't changed. I've maybe been using the A/C more with the heat but in past summers I don't remember the mileage dropping like that. Any thoughts?

 

My mileage hasn't changed at all since I got the car (Aug. '06). I would suspect there's definitely something going on there.