Canadian_S13

k, I am having a big problem with my CA18DET. I have a exhaust leak coming from one of the gaskets from my turbo, forgot which one right now, not a huge deal....so I thought. I wasn't going to fix it because I have a new manifold and also a turbo on the way, I can deal with the loud exhaust noise. So everything is put back together and now after driving it for a couple of minutes it will studder, shake, jolt like nobody's business. I'll be cruising in 3rd or 4th it doesn't matter which gear and after a couple of km, stop turn around, it then sounds as if the engine is turned off, then loud exhaust leak noise with the jolt forward, shutter and shake, engine lights comes on sometimes but shuts off. One I get to higher RPM(over 3700) it doesn't do it that much. After we turn the car off think about, try something, it runs fine for a couple of km then it starts to act up. All we did was tighten the down pipe bolts because they were loose. So we losened them a bit, just undoing what we fixed and...well by no surprise nothing changed. Please help me out here!!!!