Hi, before i did the head gasket i accidentally bent intake valves on cylinder 4. I took off the head, brought it too a head machinist he changed the valves for me, and all of the valve stem seals, checked the cylinder 4 for leaks. I put on the head, fired up the car it was running nicelly except for the ticking, but it stopped after some time, because that was one of the hydraulic lifters. Drove the car out of the garage everything was nice. Put it into first gave it a little gas everythings good, a little more gas and starts shaking, and no power at all, let the gas pedal just a little bit and you can feel power coming back, and then if more gas starts shaking again, and a very bad smell of catalytic converter. Worst shaking happens up until 3-3.5kRPM when driving. When it idles, sometimes the RPM drop a little bit starts shaking, and then corrects itself and keeps doing that for sometime, until it runs nice again. If i start to rev it a little bit, it revs not smoothly 1-2kRPM, and then its like suppose too. Anyone what it can be? To me it looks like its something with air or fuel.