Mysterious Cylinder Misfire at or above 4000 RPM
06-03-2018, 12:51 AM
#1
Junior Member
Thread Starter
Mysterious Cylinder Misfire at or above 4000 RPM
2 days ago coming home from work late at night, I put my foot down to the floor getting on the highway, but did not feel the usual kick back or acceleration. Immediately after I was greeted with a check engine light, got home and it read P0308 Cylinder 8 misfiring. Ive since cleared the codes, swapped coils, bought new plugs, cleaned out the air intake. But every time I rev over 4k, the same code "Cylinder 8 misfire" keeps popping up, and the computer shuts fuel flow to cylinder 8. Ive inspected a few vacuum lines, they seem fine so far. This is the M113 engine with 2 spark plugs per cylinder. What really gets me is that the car behaves perfectly under 4000 RPM, no vibrations and idles just fine. Has this happened to anyone else before? Could it be the fuel injectors, or MAF?
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Chris209 (11-20-2019)
09-16-2019, 07:57 PM
#2
What was the problem?
Hi! I’m having a very similar problem. I’ve replaced just about everything at this point. Did you ever figure out what the problem was?
Any help would be greatly appreciated!!
Any help would be greatly appreciated!!
2 days ago coming home from work late at night, I put my foot down to the floor getting on the highway, but did not feel the usual kick back or acceleration. Immediately after I was greeted with a check engine light, got home and it read P0308 Cylinder 8 misfiring. Ive since cleared the codes, swapped coils, bought new plugs, cleaned out the air intake. But every time I rev over 4k, the same code "Cylinder 8 misfire" keeps popping up, and the computer shuts fuel flow to cylinder 8. Ive inspected a few vacuum lines, they seem fine so far. This is the M113 engine with 2 spark plugs per cylinder. What really gets me is that the car behaves perfectly under 4000 RPM, no vibrations and idles just fine. Has this happened to anyone else before? Could it be the fuel injectors, or MAF?
The following users liked this post:
biker349 (09-17-2019)
11-20-2019, 01:11 PM
#3
2 days ago coming home from work late at night, I put my foot down to the floor getting on the highway, but did not feel the usual kick back or acceleration. Immediately after I was greeted with a check engine light, got home and it read P0308 Cylinder 8 misfiring. Ive since cleared the codes, swapped coils, bought new plugs, cleaned out the air intake. But every time I rev over 4k, the same code "Cylinder 8 misfire" keeps popping up, and the computer shuts fuel flow to cylinder 8. Ive inspected a few vacuum lines, they seem fine so far. This is the M113 engine with 2 spark plugs per cylinder. What really gets me is that the car behaves perfectly under 4000 RPM, no vibrations and idles just fine. Has this happened to anyone else before? Could it be the fuel injectors, or MAF?
11-26-2019, 08:15 PM
#4
Did you find issue my car does exact thing before reving up to 4 rpm or driving past 40 mph i have no code and fuel injector fires i could hear it ticking with a screwdriver but after i rev past 4 rpm or drive past 40 rpm it misfires and injevtjr stops ticking while other still tick
I ended up having two issues.
1. The misfire over 4K RPM was caused by some computer thing. I believe it might have been the sensor rotor adaptation or something like that. The dealer “wasn’t able to fix it” but they somehow unintentionally did. I think they reset almost everything related to it so who knows for sure.
2. I still had a slight shake at idle afterwards that turned out to just be a coil pack going bad.
Hope this helps!
-Cody
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biker349 (02-28-2020)
02-28-2020, 10:44 AM
#6
my catalytic converter was clogged unbolt it and drive it will be loud but you'll see if your problem goes away or not or remove 02 sensor before and after cat fill up tank n drive
02-28-2020, 10:48 AM
#7
2 days ago coming home from work late at night, I put my foot down to the floor getting on the highway, but did not feel the usual kick back or acceleration. Immediately after I was greeted with a check engine light, got home and it read P0308 Cylinder 8 misfiring. Ive since cleared the codes, swapped coils, bought new plugs, cleaned out the air intake. But every time I rev over 4k, the same code "Cylinder 8 misfire" keeps popping up, and the computer shuts fuel flow to cylinder 8. Ive inspected a few vacuum lines, they seem fine so far. This is the M113 engine with 2 spark plugs per cylinder. What really gets me is that the car behaves perfectly under 4000 RPM, no vibrations and idles just fine. Has this happened to anyone else before? Could it be the fuel injectors, or MAF?
