I got a miss firing code on cylinder#1, I changed the power pack coil, wires and gapped and replaced sparkplugs. It doesnt seem to miss fire when Im on the highway but driving around the neighborhood, after driving around for like 30 minutes, I look power on acceleration and smoke comes out of my tail pipe. not blue but darkish smoke. it recovers well if I accelerate the pedal lightly. currently I have the battery disconnected to clear the code. originaly the computer code was cleared and i want to get a better reading from the computer to see if something else shows up. I read on forums that it could be egr valve cam/shaft sesor or fuel injector, the timing belt was recently replaced along with the valver cover gaskets. The egr valve has oil residue around it but is this normal?