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Hi everyone, I'm new to the forum and would like some advice from anyone who can help. I own a 2008 BMW 3 series e90 m sport and recently had a diagnostic done after noticing a slight misfire and the check engine light coming on. The diagnostic found five faults in the ECM and they are as follows: 2AF4 Nitrogen Oxide Sensor, electronic / 2AF2 Nitrogen Oxide Sensor, lambda linear / 2AF6 Nitrogen Oxide Sensor, lambda binary / 2EF7 Map Thermostat, activation / 29CF Combustion misfires, cylinder 3 I've been looking online for information about nox and lambda sensors but while i feel i have a small understanding of them i'm not sure i understand them entirely. If anyone is able to shine some light onto the issue that would be really helpful. I know I could take it in to a mechanics but if i'm able to do it myself then i'd prefer to do that as I quite like working on my car and who doesn't like saving a little money by doing the job themselves. Thanks in advance. Nathan.
When I talking about misfire some days ago, got a comment saying that she had misfire before and it turned out to be sensor issue. Then it occurs to me that there is an occasion that sensors are working fine, the actual problem is AFR inappropriate. The syndrome of this problem could be car shaking/trembling, idle speed goes too high and too low, even misfire. So I use my Topdon Artipad to scan the DTC, and got P0171. There are many possible reason for this code, you can google it, but I will summarize the essence is too much air too little fuel. When AFR is incorrect, it actually means fuel is less and air too much, the essence is too much O2 in emission. For fuel system, when air intake is fixed, the AFR will be incorrect if fuel intake is low due to component issue. For exhaust system, when air intake is fixed, air leak, O2 sensor and AFR sensor detect and exhaust system related EGR should also be considered. For the intake system, when air intake is fixed, sensor features change, leads to fuel intake less than normal. For ignition system, when air intake is fixed, what’s the reason? Think about it, when misfire, mixed gas not completed burnt, O2 sensor or AFR sensor detect too much O2 in exhaust pipe. Some inexperienced technicians might think O2 sensor and AFR sensor broken that cause this problem. But I think the exact opposite, the sensors are working just fine. P0171 and P0172 are generated because they are monitoring, but, if you don’t fix the issue asap, sensors will be dead after a while. For my last article on misfire, you can click to my profile or search "my shallow analysis on engine misfire".
So i have e 4 cyl. 2.0L Chrysler Stratus LE Automatic, 16 Valve DOHC. Problem: 1. Ticking noise in engine. Probably a valve, right? (I have hydraulic tappets) 2. Main problem. Whenever i hit the pedal to the metal, or push it too quick, or im in a steep hill standing still and trying to start driving, the car jump to 3 cylinders. Even had it going at 2 once... I pull out the ignition tubes that go down to the spark plugs and it runs the same, so it doesnt ignite. But why? If i press the pedal slowly and im on a flat road, the car drives on 4 cyls. But if i press the pedal too far too quick it switches to 3 cyls. Again. The AMS (air mass sensor) is not broken as the car fucks up if i unplug it. So i was thinking maybe a injector? But i dont know. I think it's weird its only happening when the engine is under heavier use. Pls help.