420an/t Bad idle running rough/rich (FMU/Fuel pump)

[Brax93]

OK Still having problems with my 99 eclipse n/t. Recently put in new transmission runs fine but engine is running rough and now running rich I can smell the gas and voltage is funky, blinker on I can see the brake light pulse.

But the thing I'm confused about is, he has a new fuel pump (pretty positive cause of the terrible rewire he tried to do) so I did the proper rewire to try and fix the voltage dropping still didn't.... and he has what I think is a FMU connects to the fuel rail under where the cruise control box under the hood is and I discovered rear o2 sensor is broken.

One question is why need a new fuel pump and FMU if it isn't turboed? And if anyone can help with rough idle/rich/voltage problem please post.

 

[NoHndlbrsRqrd]

If the rear o2 is bad I would fix it and check the front one too. Bad front o2 will cause a rich condition and a bad idle

 

[Brax93]

Well Ill check those o2 sensors and one another forum I read they said the fuel return line from the FMU could be too small causing it to too the same thing so I might have to run a larger return hose to the pump. anymore suggestions if thought of.