If what you first described as a "sparking sound," could be called a fairly loud "ticking," then there are a couple possible sources.
First, check to see if it could be injector ticking. There are some threads regarding upgraded grounds that appear to address that (although injectors may make some noise, they shouldn't be very loud). Search for the threads.
Second, the dreaded manifold cracks... the tick should be pretty noticeable at idle.
Before freaking out too much, see if you can isolate the source of the sound a bit, perhaps using a mechanics' stethoscope (or homemade facsimile of one using plastic tubing).
Good luck and Merry Christmas!
First, check to see if it could be injector ticking. There are some threads regarding upgraded grounds that appear to address that (although injectors may make some noise, they shouldn't be very loud). Search for the threads.
Second, the dreaded manifold cracks... the tick should be pretty noticeable at idle.
Before freaking out too much, see if you can isolate the source of the sound a bit, perhaps using a mechanics' stethoscope (or homemade facsimile of one using plastic tubing).
Good luck and Merry Christmas!
