Toyota Repair: 99 solara, fuel injector problems, intake plenum

Question
I am working on a 99 solara se v6 with california emissions. It came to me after other shops had replaced spark plugs, coils, and fuel filter. I checked the codes and there was a p0171 code and another that was multiple cyl. misfire. I ran all the diagnostic checks and came up with nothing. I noticed that the itake plenum and throttle body were gummed up so I cleaned them up and put everything back together. The car ran like a top for about fifty miles and the check engine light came back on. This time it was a code for the idle circuit. I then took the iac valve off, should have done it before, and cleaned it. Now it sets the same code right away and runs terrible. Two injectors are not firing. The iac valve checked out ok but it seems like I created this problem after I cleaned the throttle body and intake plenum. Any ideas? Thanks, Bryan

Answer
You didn't create the fuel injector problems. (Unless you took a hammer to the harnesses hahahahahaha) Those were the lean bank problems all along trust me.
New fuel injectors = good to go.
The owner should be informed that the failure rate of Toyota fuel injectors is just outstandingly, low.

Seems to me like the other shops are sorta dumb, or they jsut wanted to take the owner for a $$$ ride.