[jdmccright]

Yet another case where it is hard to diagnose from afar...a noise can be described a thousand different ways.

I don't know how your engine's electronics are laid specifically, but there are sensors galore to help the engine's computer, called the electronic control module or ECM, keep tabs on what's going on under the hood: how much air is going in, at what temperature and pressure, when to squirt the gas and how long to squirt, firing the spark plugs at the right millisecond when the crankshaft is in just the right position while spinning at 3,000 rpms, then also making sure no fuel is wasted, and any that is is taken care of by the catalytic converter, etc, ad nauseum. In short, it is a complex electronic dance that can easily be disrupted by one malfunctioning part.

In your case, it could have been caused by failing spark plug coils (they can be pricey), though to have two fail at the same time is unusual. But having that happen throws off the timing for the other sensors, notably the vehicle speed sensor and the crankshaft position sensor that helps determine what gear you should be in for the engine speed, load, etc. The ECM will compensate the best it can to continue to allow driver operation albeit at a reduced power, speed, etc., in an attempt to limit any potential for engine damage.

Another possible explanation is that the electrical system that controls your spark plugs may fire more than one plug at a time simultaneously. This doesn't hurt the cylinder getting the extra spark and can help scavenge any leftover fuel. The caveat is that if that circuit fails, you've got not one but two cylinders not working well, if at all.

But we're glad you got an answer and thanks for posting back with the solution.