1992 Camry LE - was driving it and it kept momentarily stalling. Got home, popped the hood, was looking at the engine and it just quit. Replaced all four spark plugs (what a job that was - two boots came off and fell in around the plugs!) but now the sparks are not firing. Tested the modules and all fuses are good to go. Talked with the dealer mechanic and he suggested it may be the ignition coil. Where is that located? How can you tell if it is bad? Any other suggestions?

First, Are you sure there are no spark at all? Ignation coil is located inside the distributor and this part is not cheap and usually is not returnable. If you don't know much about the engine,please consider ask or hire someone who knows. After you reinstall the coil you also need to adjust the timing, wrong timing will make your car run very poorly. You might want to check the igniter as well, but ignition coil on camry is commond on high mileage.

We checked by taking one of the spark plugs out, still hooked to the spark plug wire, and layed it on the manual, turned the car over and saw no spark at all. We also tested the main engine module and know it is fine. We asked the main Toyota mechanic in town and he was the one that suggested the ignition coil. So, it is in the distributor, not on the outside? Is it hard to change?

you have mention that all the fuse is good, i just want to make sure to double check AM2 fuse (30A). To answer your question if it is hard or not? well....it is really depend....Anyway if you want to do it yourself i can email you.

The coil on a 92 4 cyl is in the distributer.
Mine just failed and I identified the problem and swapped it in an afternoon.
Its a little tricky to get out.
To get at it, remove distributer cap and rotor.
Some rotors are on tight, so if you pry, do it at the top and bottom at the same time to avoid breaking the top tabs of the coil cover. If you do no biggy though.
Buy the Wells Brand (its brownish red and available at Autozone) Fits better than black ones (Advance?)
So, after rotor pop off the cover over the coil/distributer. Wiggling usually works, or pry appropriately at the 2 bottom tabs.
Coil is at the bottom. Has 2 nuts with wiresattached to the top.
Test resistance between 2 posts + and -. Spec. 0.4-0.5 ohms but usually they are more like 0.6 even new.
That will probably be OK. Then test + (left) to high tension. (little metal tab sticking out below and between posts). The spec is 10.2-14.3 k ohms. 100 to 200k ohms or more is typical of a failed one.
Last is to test between (-) post and ground should be infinity.
Mine failed both of last 2.
2 coils in 300k miles for me.
To remove it with distributer in is a little tight.
There are 4 screws underneath. 2 you can see ends of at front of coil. To access all of this it is best to remove the air filter and hose. Big help. Even for cap and rotor. I used a ratcheting wrench with bit. Put something under car if on driveway to catch screws, they try to get away. Disconnect 2 nuts and wires and remove coil. Loosen nuts before removing all screws though.
note the specs are ohms and k ohms.
Any questions let me know.

300+, thank you so much for your guidance. We will be working on it this weekend. Your tips and advice are very helpful and very much appreciated!

300+, We got it!!! We ended up taking off the distributor but got the timing back to where it was. The ignition coil was cracked at the bottom and oil was getting out the bottom. Thank you so much for all of your help, advice and support. You are a gem!