Help! Misfire in Cylinder 3 & 6 but Runs Fine
11-12-2018, 05:05 PM
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Join Date: Nov 2018
Location: Arizona
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Help! Misfire in Cylinder 3 & 6 but Runs Fine
Hi guys,
I am new to this page so I hope this is in the right thread.
Anyways, I have a Stage 2 Roush SOHC 4.6L. I am experiencing some issues with misfires but the car runs fine. The misfires recently have been 3 & 6 mainly and one with cylinder 1. To start off, I had put on a cold air intake, full bolt on exhaust from headers to tips running no cats, with mama tune for 91. I began experiencing these issues shortly after. It first threw a code for a bad O2 sensor upstream w/ lean code, so I replaced both O2 sensors upstream and put high flow cats on. Code for lean was still left over and the P0300 (Random Misfires) & P0306 (Misfire cyl 6) showed up. I cleaned the MAF and the lean code went away and hasn't been back. Now, I am just left with a intermittent Cyl 3 & 6 misfires which it'll got back and forth between them or both will pop up. Sometimes my check engine light doesn't come on but I run OBDII on the daily. I have replaced the plugs in both cyclinders and I have swapped coils. I ran injector cleaner a few days ago and had a 3 step fuel system clean a few months ago, so I doubt its the injectors. My car runs like normal.....No stalls..... Every once in awhile at idle it does a super quick bog and returns to normal. Car seems to have full power. I am out of ideas.
Hope someone can help.
Thanks
Eric
I am new to this page so I hope this is in the right thread.
Anyways, I have a Stage 2 Roush SOHC 4.6L. I am experiencing some issues with misfires but the car runs fine. The misfires recently have been 3 & 6 mainly and one with cylinder 1. To start off, I had put on a cold air intake, full bolt on exhaust from headers to tips running no cats, with mama tune for 91. I began experiencing these issues shortly after. It first threw a code for a bad O2 sensor upstream w/ lean code, so I replaced both O2 sensors upstream and put high flow cats on. Code for lean was still left over and the P0300 (Random Misfires) & P0306 (Misfire cyl 6) showed up. I cleaned the MAF and the lean code went away and hasn't been back. Now, I am just left with a intermittent Cyl 3 & 6 misfires which it'll got back and forth between them or both will pop up. Sometimes my check engine light doesn't come on but I run OBDII on the daily. I have replaced the plugs in both cyclinders and I have swapped coils. I ran injector cleaner a few days ago and had a 3 step fuel system clean a few months ago, so I doubt its the injectors. My car runs like normal.....No stalls..... Every once in awhile at idle it does a super quick bog and returns to normal. Car seems to have full power. I am out of ideas.
Hope someone can help.
Thanks
Eric
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