Well, the EGR code is NOT because of a cold engine. The guy who pulled your codes obviously does NOT know how powertrain control modules can actually
store codes for later retrieval. The actual sequence probably looked like this:
11
11
*pause*
-1- (divider code)
*pause*
33
41
33
41
The first "11" means that
as the system is sitting there, there aren't any problems with the sensors or actuators. Everything checks out okay under static conditions. Good start.
The next series of codes were tripped sometime within the last ~50 times the engine was running. These codes are stored until the problem clears up or is repaired, and then the EEC-IV is sort of like, "oh, nevermind," if it's fixed or goes away.
A code 33 (if it's for EGR, I'm not sure, as I don't have my chart handy) means that the computer has seen insufficient EGR flow during operating conditions. This could mean a few things could be wrong, but I'll point them out in the order I'd check them:
1. A leaking (more than likely cracked) vacuum hose somewhere between the vacuum tree on the firewall and the EGR valve. Remember this includes the lines going to the EGR regulator that's on the firewall side of the passenger side strut tower. Those plastic lines get brittle with age, and this is very common for them to crack. Check the entire length of each line, and also their branches!
2. The EGR position sensor could also be crapping out, also common on older EEC-IV controlled vehicles. It's the white plastic thingy bolted onto the back of the EGR valve with three nuts. You may want to remove it anyway and be SURE the silicone seal is still intact. That seal is the only thing that keeps vacuum in there, so if it's leaking at all, the valve will not open ever.
3. The EGR valve could just plain be stuck shut from carbon buildup. Just remove the valve by the two bolts holding it onto the EGR spacer (they are two different size nuts, 1/2" and 9/16" I think, so the valve can only go on one way), get a new EGR gasket (about $0.99) and a can of carburetor cleaner (NOT THE FUEL INJECTION STUFF!!! It just doesn't eat grime off like carb cleaner), and spray the pintle valve as you move it in and out. The passages should also be cleaned, but then you already knew that.
Okay, on to the next code...just replace both oxygen sensors if it hasn't been done in the past 30,000 or so. Be sure to remove the battery cable (take your pick) when you do this so the computer's keep-alive memory is erased. This way you can a) get better gas mileage, b) have more power because the computer will be able to better calculate the a/f ratio and other parameters, and c) so you know the computer or sensors aren't full of horse-pookey.
You know, there is a slight possibility that you could be getting BOTH codes from a SINGLE vacuum leak. That leak could be preventing the EGR valve from opening, AND be leaning out the mixture on the one bank. Sounds nuts, but I've seen it happen. Good luck to ya.