hello mazda world,
im trying to get rid of my check engine light on my 00' milly s. the codes i get back are PO170 (fuel trim malf.) and PO304 cylinder #4 misfire. Does anybody know if cylinder #4 is in the front or the back of the engine. Also, it seems to me a fuel injector is the problem, but im not sure if its the electrical unit or the injector itself. Any help??

 

p0170 is right(rear) bank. most likely, a vacuum tee is cracked. there are several, and they will cause you all kinds of problems. the 2 most common are right between the banks, you have to remove the part of the intake that is attached to the compressor to get to them. #4 cyl is left(front) bank. front bank is 2-4-6. easiest to get to. i really doubt it is the injector. way more common is the coil. might be oil in the wells, too. that can cause misfire.