My husband changed the plugs and wires for my fathers Chevrolet 1992 cavalier wagon... now it's not running as well as before he replaced them and he's concerned they are not in the right firing order... i need a description or diagram of the firing order for a 1992 Chevrolet cavalier wagon

easiest thing is to search it on google and youtube. there are a lot of how to videos on there. May i ask what is wrong with your brakes?

The computer can be in the engine compartment or behind the dash inside the passenger compartment.
But I doubt the problem is the computer. I would check for power at the ignition switch first. If you have power in and out of all circuits with the switch on, next would be the relays.

code 66 is the a/c pressure switch. which will not make car run rough and stall unless its back feeding power. run engine with ac off and unhook connector to high pressure switch. the most common reason for running rough could be a bad sparkplug or sparkplug wire, check the wires and plugs also check dist cap and rotor for arcing. and last is how old is the o2 sensor, a bad o2 sensor can also cause this problem.

If the car sat for a year or more you have bad gas (turns to varnish) Drain and refill and use some good injection cleaner

I would try replacing the fuel pump relay.

drilling a hole in each rivit or headless bolt and using a easy out
fun, fun, fun

Also, make sure the plug wires are on the plugs and are well connected.

well first you need to perform a compression test, this will tell you right up front of you have major engine trouble be it head gasket, camshaft, cylinder rings etc. First things first what do the spark plugs look like after it has benn running for a while??

replace the fluid in the transmission with the new DEXRON 6 fluid, it in many cases this new synthetic fluid solves this kind of problem, also replace the fluid filter while u are at it.

replace distributor cap and rotor btton. hope this helps