Possibly bad injector?

pajkrubi · December 24, 2019

Hello everybody, tonight while driving my 2014 Silverado with the L83 5.3 (102,000 miles) my check engine light started flashing and the engine had an obvious miss. I pulled the code and got a P0305 (cylinder #5 misfire). I drove it gently home and checked the plugs and wires. I just recently did new plugs and wires (factory AC delco iridiums and taylor street thunder wires) so I didn’t know if one came loose. Everything was tight so I pulled the plug. The plug looked nice and clean with no broken electrode or anything obviously wrong. So I swapped the coil pack from cylinder 3 and took it for a short drive until the cel started flashing again. Got it home and it still said cylinder 5 misfire. I swapped the plug and cable from cylinder 3 then just to see if the inside of the plug or cable was broke. Came back still showing cylinder 5. The plug also seemed dry for not firing so I started to wonder if it’s fuel. After searching I see the direct injectors in these motors are pretty much garbage and fail regularly. Do you guys think it’s probably the injector or could it maybe be a failed lifter from the afm? I’m hoping it’s an injector because I’ve watched a few videos and it doesn’t seem horrible to do. I’m pretty mechanically inclined and have all the tools. I’ve read about the teflon seals but saw a few tricks to get them on. Also if it’s an injector I’m thinking about just replacing all 8 since you can find them for pretty decent prices online. I also know about needing to replace the hard lines also and will be doing that. What does everybody think? Most likely an injector or is it something much worse like a lifter? Side note and not sure if it matters but I’ve ran E85 for about the last year or so in it but seeing as how it’s a flex fuel I don’t that would matter. Thank you for any help you can give.