Hi..Diagnostic machine says my dodge nitro 3.7l has a misfire on cylinder 1. Mech changed the coilpack on cylinder1 and it worked for a few days after restting and then started misfiring again. The mech then asked me to change the fuel injector on cylinder1 which we did. The vehcicle drives perfect for a few days after restting with the diagnostic machine but then it starts to misfire again. Please advise, i have been to two mechs and both used diagnostic but cant solve it?

 

Have you tried changing the plug?

Moving this to the Nitro section for ya.