Leg4Life Posted June 7, 2018 Share Posted June 7, 2018 2008 LGT SPEC B - So i got these codes about a month ago and replaced the coil packs and spark plugs. The first time was 301-304 so all four but after replacement of spark plugs and coil packs only 1 and 3 show misfire codes. I reconnected the wires and reset the engine and 2 weeks later the p0301 & p0303 came back for a second time after being replaced... Any suggestions? Sent from my LG-LS997 using Tapatalk Link to comment Share on other sites More sharing options...
ehsnils Posted June 7, 2018 Share Posted June 7, 2018 Well, you should post in the 4th gen forum, but it can be a number of things, ranging from headgasket to oil control valves, valve clearances or even ringland failures. Link to comment Share on other sites More sharing options...
relative4 Posted June 7, 2018 Share Posted June 7, 2018 How many miles? What mods & tune? What diagnostic equipment do you have? If you have BtSsm or RomRaider, a great starting point is to post LV, next to watch roughness/misfire counts and see if you're still having misfires on all 4 cylinders, just not enough to trigger codes on some cylinders. If you don't have either of those options, you will at least need a scanner with live data so you can see LTFTs & misfire counts at idle, 2500, & 4000 RPM. Link to comment Share on other sites More sharing options...
Leg4Life Posted June 7, 2018 Author Share Posted June 7, 2018 Thanks for your responses! My LGT has 102k miles on it and I have no equipment to diagnose it. Sent from my LG-LS997 using Tapatalk Link to comment Share on other sites More sharing options...
relative4 Posted June 7, 2018 Share Posted June 7, 2018 Then I take it you're running the stock tune? No mods? To diagnose this, you need live data. I heartily recommend an OBDLink BlueTooth dongle and the BtSsm Android app. Link to comment Share on other sites More sharing options...
Max Capacity Posted June 8, 2018 Share Posted June 8, 2018 Find a good local repair shop and see what they will charge you to find out whats wrong and let you fix it if it's easy. I assume you have replaced the timing belt kit already ? 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Shawn06SpecB Posted June 10, 2018 Share Posted June 10, 2018 failing oil control valves, OCVs, can cause misfires on 1/3 or 2/4. They're around $100 for OEM replacements Link to comment Share on other sites More sharing options...
relative4 Posted June 10, 2018 Share Posted June 10, 2018 failing oil control valves, OCVs, can cause misfires on 1/3 or 2/4. They're around $100 for OEM replacementsYes. Definitely replace expensive parts at random with zero diagnosis. Link to comment Share on other sites More sharing options...
Shawn06SpecB Posted June 10, 2018 Share Posted June 10, 2018 Yes. Definitely replace expensive parts at random with zero diagnosis. They should be considered preventative maintenance anyways. What suggestions do you have for the OP with the little information provided? Link to comment Share on other sites More sharing options...
relative4 Posted June 10, 2018 Share Posted June 10, 2018 They should be considered preventative maintenance anyways. What suggestions do you have for the OP with the little information provided?OCVs are NOT preventive maintenance. See post #5. Link to comment Share on other sites More sharing options...
Shawn06SpecB Posted June 10, 2018 Share Posted June 10, 2018 OCVs are NOT preventive maintenance. See post #5. See post #4 He has NO diagnostic equipment and has already been throwing parts at the issue haphazardly. Link to comment Share on other sites More sharing options...
relative4 Posted June 10, 2018 Share Posted June 10, 2018 Thus post #5. Link to comment Share on other sites More sharing options...
Leg4Life Posted June 11, 2018 Author Share Posted June 11, 2018 Thanks for your feedback everyone. I will probably be taking it to a shop to have them run the diagnostics and will let you know. Also in response to the other questions yes tge timing belt was done around 101,xxx so only about 2k miles on the new timing belt and running stock everything... Sent from my LG-LS997 using Tapatalk Link to comment Share on other sites More sharing options...
Leg4Life Posted July 16, 2018 Author Share Posted July 16, 2018 I have good news it was the timing belt so I took everything apart and redid the timing belt make sure of all the timing marks were correct and no misfire. Sent from my LG-LS997 using Tapatalk Link to comment Share on other sites More sharing options...
ehsnils Posted July 18, 2018 Share Posted July 18, 2018 Good that you got that fixed! Link to comment Share on other sites More sharing options...
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