Hello, new member here.
2003 s type v6
While driving on the hwy my restricted performamce light came on but once i got off the hwy and came to a stop the restricted performance turned off but the check engine signal remained on. got the codes read and came back with p0174 lean on bank 2 theres no air leak and all o rings were replaced about 2 month ago also air filter fuel filter have been replaced. The car was put thru a computer and oxygen sensors read fine everything reads fine except the MAF sensor it has no reading it remains at 0 cleaned the sensor and no change it does not read anything its still at 0. the engine runs perfect but i get the restricted performance message for small period of time.

 

Did you do the service yourself? You say that there is no air leak but it sounds like that is what you have. Have you checked the MAF connector? Is the plug connected properly. I would start at the air box and go over each and every clamp and connector. These cars are very sensitive to air flow and even a slight leak can trip all kinds of codes.

 

I agree. It sure sounds like an air leak problem....

 

Imts are not the only leakers, upper and more so lower intake manifold gaskets are becoming big issues as well now that theyre getting aged. If you can monitor mafs, im assuming your useing a scanner, monitor short term fuel trims and spray with carb/brake clean and watch fuel trims to monitor were youre getting leakage. If you have a zero'd mass air flow sensor you will have a code for that. While mafs can creat rich/lean codes, it is not common on the s type

 

MAF reading 0 should only be at engine off. If on, something is probably shorted (whether to batt or gnd). Try MAF unplugged. The PCM will default so you should not get 0. If you do, you have a short or maybe a blown PCM (unlikely). Start checking wiring for shorts...

 

thanks for all the replies.
I did not do the serivice myself, it was done by a mechanic 2 months ago i had to change my valve cover gaskets since they had to remove the maf i figure i change everything that could be replaced, i replace all hoses all seals and gaskets, spark plugs. my maf reading is at 0 when my engine is on even if i rev the engine it stays at 0. the restricted performance came on last week.
brutal and jagv8 i will try both of your suggestions today.
thanks guys