Hi fellas I have a 2008 ford fusion i'm trying to diagnose. Firstly the smog pump is out and that's all I have a code for, tested the smog pump directly it isn't working. I would've replaced that and went from there but there's something else wrong I can't see the smog pump being out making this car as bad as it is. This is an auction car so it can definitely have multiple issues lol. I put new plugs in it, ran it for a minute or two, they're pitch black with soot. The 02 sensors stay pegged at .9 volts. When it did run in closed loop it would run ok but watching the fuel trims it would quickly keep pulling fuel out until it got to -28 or so and couldn't pull anymore out then it would kick into open loop and run like crap/stall/not start. It would actually rev up with throttle a few times and run pretty decent. But in general it has a terrible idle and won't take throttle, when it's in open loop which it's pretty much stuck in now. The reason I'm not ordering a smog pump and calling it done right away is because even if that would out I know it can make it run rough but I can't see this bad.

At this point the thing at the top of my list is clogged exhaust. I don't feel like that's it even though it seems the most likely but it did rev up with some throttle when it was in closed loop and would seem fine sometimes. I am going find a way to test backpressure or at least pull the exhaust a part and see if it runs any better or if I can see anything.

This car doesn't have a fuel rail pressure sensor!! that would've been my first guess but it doesn't have one lol. I cleaned the throttle body and maf sensor. The maf sensor seems to be working although of course it could be off at idle it shows something like 6g/s and that's without the smog pump running so now that I consider that...it seems like it could be over estimating the amount of air coming in which of course would lead to it dumping more fuel in, what do you think? I have a ranger of the same year with the same 2.3 I might swap the maf's out and try. first I should compare some numbers on the scanner to the 2.3 in my ranger should be the same

Any ideas or thoughts would be appreciated