Hey everyone, I drive a 98 GS, and a few weeks ago I decided to put the OBX intake manifold that was sitting in the back of my garage for months and attempt to put it on. This was needless to say a bad idea. After removing the stock manifold, I tried putting my stock injectors in the OBX manifold, they didn't fit. After MUCH deliberation I decided to put my old manifold back on, and after resetting my ECU, I still had a check engine light.
My car was running fine, but after a few weeks I noticed a decrease in performance and gas mileage. I checked the manifold, and it appears I overlooked a hose. I've attached two pictures of the place where I believe a hose is missing, if anyone is able to tell me what this would be, it would be greatly appreciated.

Here are the photos.





Thanks, Nick.

It's a vacuum hose related to evap that goes down the back of the firewall and under the car. You'll find the hose hanging around the alternator if you get under the car with a flashlight.

Yup, that's correct. The one on the right is your EGR, the center is your cruise control and then the EVAP. It shouldn't really effect your MPG all the much though. That's kinda werid.