Might be mechanical. Springs, trunnions, and even worse. Lifters. In my case it was a lifter.
Random P0300 odd side only
So recently during a random drive vehicle started misfiring. The day prior I was doing pulls without any issues and now it’s missing. I went home and check HPTuners and it’s showing cylinders 3/5 misfiring terribly. I moved coils, wires and plugs, didn’t help. I then sent out all the injectors to a shop to get flow checked and they were fine (only cylinder 4 injector was decreased by 9.3%). I went home and put it together and misfire remained. I performed a compression test and got:
1)144
3)135
5)140
7)142
Test was done dry and cold. Looked at HPTuners and thought maybe the O2 is fowling. Replaced the O2 with a new NTK and now it’s misfiring form 5/7. I tried to do a power balance test and went I shut off any cylinder now it’s about to stall out (doesn’t), but if I unplug a coil it idle the same exact way unless I pull an even coil and it does stall out. I’ve reviewed the logs multiple times and also checked the ground on the head in the front. Also tried to swap harness coils from side to side as well with the coils being jumped as well. I’m at a loss at this point and don’t know what to do. Including the last log and some other pictures I took. It is a 2017 with a 1.9 TVS Maggie(ported and overdriven 70%), 1300ID injectors, American racing 2in long tubes, icebox, DSX aux and flex kit. Bone stock sealed motor as well.
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Log File
1)144
3)135
5)140
7)142
Test was done dry and cold. Looked at HPTuners and thought maybe the O2 is fowling. Replaced the O2 with a new NTK and now it’s misfiring form 5/7. I tried to do a power balance test and went I shut off any cylinder now it’s about to stall out (doesn’t), but if I unplug a coil it idle the same exact way unless I pull an even coil and it does stall out. I’ve reviewed the logs multiple times and also checked the ground on the head in the front. Also tried to swap harness coils from side to side as well with the coils being jumped as well. I’m at a loss at this point and don’t know what to do. Including the last log and some other pictures I took. It is a 2017 with a 1.9 TVS Maggie(ported and overdriven 70%), 1300ID injectors, American racing 2in long tubes, icebox, DSX aux and flex kit. Bone stock sealed motor as well.
1 - 13 of 13 Posts
NOT TRYING TO BE THE GRIM REAPER HERE. MY MISFIRE MESSED WITH ME FOR ABOUT 4 WEEKS. AFTER ALL THE ITEMS YOU CHECKED, INCLUDING POPPING OFF THE VALVE COVER AND INSPECTING THE TOP END. THERE WAS NOTHING LEFT BUT SOMETHING INTERNAL. THE ROLLER ON #2 LIFTER WAS EATING UP CAM.
I READ OVER IN THE VETTE FORUMS THAT THIS ISSUE WAS GRANADING ENGINE BLOCKS. MY ONLY MOD WAS A MILD CAM AND 1.8 ROLLER ROCKERS, AND THAT HAD OVER 15K MILES ON IT. "SEE PIC". I RECORDED THAT TRIP ON THIS THREAD STARTING AT #16, VERY SIMILAR TO WHAT YOU ARE GOING THROUGH. p0302 fault code...rough idle.
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I READ OVER IN THE VETTE FORUMS THAT THIS ISSUE WAS GRANADING ENGINE BLOCKS. MY ONLY MOD WAS A MILD CAM AND 1.8 ROLLER ROCKERS, AND THAT HAD OVER 15K MILES ON IT. "SEE PIC". I RECORDED THAT TRIP ON THIS THREAD STARTING AT #16, VERY SIMILAR TO WHAT YOU ARE GOING THROUGH. p0302 fault code...rough idle.
1 - 13 of 13 Posts
