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Message: <blockquote data-quote="Jetsetter" data-source="post: 791091" data-attributes="member: 10857">My Mach picks up tons of "collapsing fields", as the electrical shop said. Then again my car took a drive into a lake.You have tried clearing the learned memory, right? I think the battery needs to be disconnected overnight.I'm not inclined to believe an exhaust leak is going to influence your engine to misfire, or perform in the way it does. I ran my car with the front O2's disconnected with no obvious performance hit. Your misfire is being influenced by three things not coming together. Your fuel, your spark, or your air is causing the issue. Your ECU meters and controls the amount of fuel delivered and when it is delivered, when the spark is fired through your coils, and the amount of air flowing into the engine. ECU's can go bad, and I know at work the transmission control module is becoming an increasing cause of returns. So we have the basis for what your engine needs, and now we can rule out controls one by one. We have generally ruled out spark, whose function is from the COP's and would generally be localized by one bad COP. I guess MAF's can go bad, but I haven't heard of it as you can assume since your car is on the surface of the planet it will be receiving air.Finally we are left with fuel. Fuel is trickier, as it is a bigger system. The elements of your fuel system will include your fuel pump, fuel filter, the lines, the rails, the injectors, and of course the computer inputs. That's simplified, but it's roughly the right ideology. You've replaced the filter, the lines and rails are probably not clogged, you've replaced the injectors, so what's left?Fuel pump? FPDM? I look at your datalogging sheet and ask myself WTF am I looking at. All I can say is you seem to have a fuel delivery problem at this point, and since you've replaced the injectors we're down to the last two things for this round of diagnosis. The way I look at things is that your fuel pump could be going out. With my 97 when the fuel pump was going out I could drive it for about 45 minutes and then the car would run rough and shut off when the pump failed. When the pump got hot and worked, then the failure would show up. With your vehicle, it may run fine until it warms up, when the pump will start to operate erratically and not deliver the requested fuel from the FPDM causing your car to misfire and eject the unburnt fuel, into your nostrils sometimes. Maybe I don't know shit and it's a vacuum leak. But there's something more to think about.</blockquote>