I would help to know what year and model vehicle you have but, you may have a bad fuel injector.
I have a 98 Jeep Wrangler that kept generating a timing problem codes, after changing the crank sensor and timing module in the top of the distributor, I took it in and they changed out the distributor and stopped the check engine light from coming on. The CPU timing specifications are so tight that a little wear in the distributor shaft starts throwing codes out. It ran fine just kept throwing codes, a rebuilt distributor fixed it.
Those are all misfire codes. The common cause would be spark plugs, wires, distributor cap, and rotor.
To clear cylinder misfire codes, you typically need an OBD-II scanner. Connect the scanner to your vehicle's diagnostic port and navigate to the trouble codes section. Select the option to clear or erase codes, which will reset the check engine light and remove the misfire codes from the system. After clearing the codes, it's advisable to monitor the vehicle for any recurrence of the misfire issue.
I had that happen n I changed my plugs n coil pack...easy to do
43 is some sort of engine misfire, or distributor fault... code 12 is that the battery has been disconnected in the last 50 key cycles...
Have you tried wires, coils or injectors?? Depending on the mileage, a compression check may be in order also. P0300 is random misfire.. P0301 refers to cylinder #1 misfire and P0306 refers to cylinder #6 misfire. Try the simple things like wires 1st... after the compression check.
id try the coil. i had p 171, p174 ,p301 which is cylinder 1 and 4 are lean and the 300 codes are misfire codes i changed plugs wires and coil worked fine
A misfire on cylinder 3 in a 1996 Blazer can be caused by a faulty spark plug, fuel injector, or ignition coil specific to that cylinder. It is recommended to perform a compression test to rule out any internal engine issues and also check for vacuum leaks. Additionally, scan the vehicle's computer for any trouble codes that could pinpoint the exact cause of the misfire.
Most obdii codes are multi-digit, such as po300,po301,po302, etc. Etc. Po300's are usally misfire codes pertaining to the same cylinder...code po302 is a misfire in cylinder #2. A po300 code is a random misfire for any cylinder
its most likely the air by pass valves and some coils that need to be changed.
A single cylinder misfire can trigger multiple diagnostic trouble codes (DTCs) because the vehicle's engine control unit (ECU) monitors various systems and parameters. When a misfire occurs, the ECU detects issues such as fuel delivery, ignition timing, or exhaust emissions associated with that cylinder, leading to codes related to each of these systems. Additionally, the misfire can affect overall engine performance, potentially triggering codes related to broader engine operation. Thus, a single problem can cascade into several related codes being logged.
If you're experiencing a persistent misfire on your 1997 Mercury Villager after replacing the knock sensor, plugs, wires, and distributor cap/rotor, consider checking the fuel injectors for clogs or malfunction, as well as the ignition coil, which could also be causing the issue. Additionally, examine the engine's vacuum lines for leaks and ensure the timing is set correctly. You might also want to conduct a compression test to rule out any internal engine issues. If the problem persists, using an OBD-II scanner to check for error codes might provide further insight into the misfire's cause.