I'm probably in the wrong forum but since it is a swap vehicle it can't be too wrong. It's late and I just got back from a round trip of about 150 miles. Temperature outside is about 28 degrees......cold, Michigan weather, and it's too late to work on it right now. Anyway, I drove to my destination and the entire way the car ran great. It wasn't until I was about halfway home when it started acting up. The entire trip was 75% interstate and the rest 2 lane roads. As I was climbing a hill along the interstate the engine began to bog and my speed dropped drastically from around 75 to barely making 60. It only seemed to affect me when I was climbing hills and not so much in staightaways. On the 2 lane roads the car ran great and I ran up to 80 with no problems on the straightaways. There were almost no hills the last bit so I can't say if it would have been a problem or not. I have a '90 hatch with mini-me hybrid swap. I used the '91 Si ecu/intake/distributor on the D16Z6 engine and it's been very strong until this point. Currently I've put around 15k miles on the engine and it only had about 40k on it when I got it. Oil's been changed every 3500 miles with Mobil 1 and the coolant was new along with a new radiator when I dropped the engine in. There have been no other mods yet as I was working on getting the Apexi VAFC II before anything else. I'm not running the VTEC although it is hooked up to a tach shift light but set too high at the moment for it to pull in. The only problem area is the exhaust.....it's broken at the intermediate pipe just past the resonator pipe and of course there's no muffler. Anyone have clues where I should start looking first....? My thinking is: slipping clutch (kinda rule that out though since it still pulls hard through the gears), possible fuel contamination in the tank (I filled that tank before the trip and lately my gas mileage has been dropping) plugging the pump.......can't come up with any other ideas ATM. Thanks for helping everyone....I appreciate it!