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Q: Misfires on a Mopar performance long block crate motor/2001 Ram 1500 offroad. on 2001 Dodge Ram 2500

The engine continues to have multiple misfires ever since It was installed in 2005. I'm running a MSD 6A ignition and just replaced the coil, battery, alternator, plugs (stock plugs), belt, cap and rotor. All the sensors on the throttle body have been replaced too.
It does it mainly at low rpm. Fuel pressure checks out good.
Any ideas?
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Start fresh and check the basics, check compression is even and strong, check there are no vacuum leaks. Many automotive repair shops have a machine that generates an inert non flammable low pressure smoke that looks similar to cigar smoke. The intake manifold is sealed off, and smoke is put into the engines intake manifold. The smoke then fills the engines crankcase and if there are any vacuum leaks from gaskets, hoses, or housing smoke emits from the source of the leak. Perhaps have the injectors tested. After that I would say you need to look at sensor data using a professional grade scan tool and look at air charge volume, O2 sensor readings and fuel trim figures and see if anything seems marginal or out of specification. There is a professional service called Identafix. They only deal with professional repair shops. They are in the Minnesota 651-633-8007 begin_of_the_skype_highlighting 651-633-8007 end_of_the_skype_highlighting. Your auto repair shop do all their diagnosis tests, and discuss your problem with a team of professional technicians great service cheap and very bright people. If the repair shop that are repairing your car are stumped this is a great service. This company only deal with automotive repair shops and don't answer questions for the general public but are an amazing knowledge base. My guess would be an injector problem if there is no vacuum leaks.
OK, I can do that. I did have the injectors rebuilt and tested when I installed the engine but that was a few years ago.
Thanks for the quick and informative response! JD.
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