Hello so I bought a brand new ECM for the forklift that I'm working on because the old one wasn't firing the ignition coil for cylinder number three so I bought a new one ecm. all cylinders fire but it only runs for about 30 seconds and then turns off and it throws a check engine code for the P1240 I plugged in the old ECM and the misfire is still there but it doesn't turn off after 30 seconds and it doesn't throw the P1240 code so I don't know if it's a defective ECM that I got or if there's a fix to it, I tried swapping out another injector from another forklift and it does the same thing I put the injector from the forklift that is having the problem on the other forklift and it runs perfectly fine. Any help would be greatly appreciated.