My 03 SSEI was missing bad under full throttle and I did the following repairs;
New Air Filter
Dropped the Cat and it had no blockage
Changed the MAF Sensor and it fixed the problem
Drove 60 to 80 miles and it starts to run a little rougher and kicks the engine light on again.
Could a bad PCV valve cause excessive oil to get in the intake and get on the MAF sensor?
I have the stock intake system in place and keep new air filters in place. She has 175k miles but does not burn oil. With the new MAF she actually ran very strong like new.
Not the new one. I am going to look at it Friday.
I was thinking about wiping it with a Quetip.
Don't use anything on the wire. Get some MAF Cleaner Spray from the auto parts store and spray the heck out of it and then let it air dry. If you touch the wire and damage it, you'll be crying when you find out how much they want for a new MAF.
It use to have a K&N but I took it out and replaced it with a hastings stock filter. I never oiled it but had concerns the factory applied oil may been coming off the filter. I will get back in town tomorrow and see what code it is throwing.