Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Having problems with this SUV, it show code random misfire number 2 and 3 cylinders, I change the sparks plugs on all cylinders and ignition coils and changed the 1, 2 and 3 fuel injectors. Took it to the dealer and the mechanic said to replace rear cat and replace the EGR valve and cleaned the intake, so I did and still no luck, I did a relearn and still random misfire P0300, P0302 and P0303. What can it be??
Did the misfire go away changing the spark plugs, and then eventually return? Or did it not improve at all?
I see quite a few of those with bad oil sealing rings. They consume oil and fowl plugs, usually on the rear bank.
the misfire still there on 2 and 3 cylinders, I took it back to the dealer, the mechanic thinks it a stuck rocker arm or faulty injector, but I change the injectors with new ones. He change around the spark plug and coils but still misfire in the same cylinders 2 and 3. I thought about the harness wire but he didn't seem to interested, but wanted to explore more, so I just brought the SUV home.
Verifying the mechanical condition is a starting point that would makes a lot of sense imo..... Do you have any freee frame data to share?
Depending on tooling and knowledge you may start with something as simple as a vacuum gauge and might end with pressure transducer analysis. Do you know wether/when the valves were adjusted?
An expert is someone who knows each time more on each time less, until he finally knows absolutely everything about absolutely nothing.
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