Originally Posted by scoogie_scott

Hello all,

I have a 2003 Tahoe VIN Z. This vehicle came with the Flex Fuel Motor. I have since put in a standard motor (non Flex Fuel). Engine seems to run great with no problems at all; however, I have a check engine light blinking at me saying multiple cylinder misfire when I get above 2500 RPM's or so. I'm using vehicle's original wiring harness. The plugs on the fuel injectors for the standard motor and the flex motor are different; therefore, I had to reuse the injectors that were on the flex fuel motor. From a little internet searching, I have found that the flex fuel injectors are rated at 35lb while the standard injectors are rated at 26lb. Might this be the reason I am getting an error code with multiple cylinder misfire? My thinking is that maybe it's injecting too much fuel or something at the higher RPM's. I'm trying to find some fuel injector wiring harness plugs with pigtails from a junkyard that will fit the fuel injectors that came with the replacement standard motor. My hope is that once I change the plugs and put the proper injectors in there, the misfire error code will go away. If I do this, is this going to require a replacement of the ECM as well? Any thoughts?

Thanks