Toyota I am trying to find out which wires go where. I know that the firing order is 1-3-4-2, but I don't understand the coil packs. The diagram that I have is confusing. It shows that the coil packs are listed as from front to back 1-2, 3-4. If this is the case, then why is the firing order 1-3-4-2? This is a 1999 Toyota Tacoma regular cab pick up 2.4ltr 2 WD. Any help will be greatly appreciated.

Coil pack connection is physical: Coil 1 to Cylinder 1, 2->2, etc.

I am not sure if this is your question, but firing order matches spark to TDC (top dead center) on the power stroke. The design of the crankshaft determines this.

1-3-4-2 is common for most straight 4's. Cylinder 1 is closest to the crank pulley. I believe your coils are 'waste spark' which means it will fire two cylinders at the same time. When the coil fires, one cylinder is on the power stroke and is wanting this spark. The other cylinder is on the exhaust stroke at this time, and thus the spark is 'wasted' on that cylinder. But a cylinder with exhaust gas has high impedance, so most of the energy is delivered to the intended cylinder.

If your question was 'should I just connect 1->1, 2->2, 3->3, 4->4' [ yes!] vs. ' should I try to connect coils following the firing order' [no] then the answer is the first. The trigger wheel determines which coilpack fires when, you just need to hook up the wires number for number.