So I as I was driving my vehicle after o2's were changed I got a p1171 and 1181 code. When researching this it said that I'm running lean, now I'm not getting the o2 codes anymore but why are these coming up? I have checked for vacuum leaks but couldn't find any, my car runs fine only thing I noticed was lack of power and this has been like this for as long as I could remember.

My boost gauge is reading -12 to -10 at idle and I'm wondering if there is some leak I can't find, does ANYONE know what the specs are for vacuum? I have sprayed the car with carb cleaner at all suspected areas, nothing came up.

When researching some people claimed to have said the mass air flow sensor is the problem, I attempted to clean it and will see what happens in the morning, I also read that it could possibly be a faulty ETM but my car isn't acting up like most people complained when there's were going out.

I'm wondering if maybe I should just replaced the MAF and see what happens, I don't have a VOLVO dealership around here, closest one is 300 miles away and the mechanic I usually take my car to knows NOTHING about volvo.

I'm running a catless cat with o2 spacers that have been working so far, when reading I was told that the rear o2's don't effect a/f ratio, the car's cat was clogged so I was told by my mechanic the first time and I ended up tearing the crap out of the honeycomb since I couldn't afford a new OEM one. I started to notice a drop in my MPG averaging around 14-15mpg and this was grandma driving, I came to the conclusion after researching that those codes were more than likely set off due to bad o2 sensors...

replaced my o2 sensors and now i'm getting 17-18mpg so far, but then these codes came up and now i'm wondering why now... :/