-1990 F-150 XLT Lariat-178,ooo miles-E4OD-two wheel drive-300 motor

I removed a sensor (forgot which one) from the intake manifold. Inside there was the black gunk (From EGR) as explained in other threads. I am going to clean the manifold and everything else i need to pull out in order to get to it.
I have a haynes manual. What should I know? I've already seen other threads and plan on using oven cleaner on the inside of the manifold. I suppose i should replace all removed gaskets as well?? Once I have this torn apart is there anything else I might as well do since it will be taken apart(injectors maybe, FPR)?
I check this site many times a day so any comments at all are appreciated!

I have this damn code 41. O2 sensor is new and so is egr system. Maybe this will fix it, but even if it doesn't it needs to be cleaned very badly
. No I havn't checked the fuel pressure yet I plan on it though

 

Fuel injection by the way...and also no codes except for the 41 and 2 tranny codes becasue it needs a new tranny

 

41 indicates an issue with the O2 sensor.

You say its new, so Id think that would indicate some kind of electrical issue between the computer and the O2 sensor itself. I doubt cleaning the intake would help your problem, much less checking fuel pressure. Just my two cents though.

If you do clean the TB and intake, make sure your sensors are nowhere close and stay clean and dry.