V10 miss under load
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Cross-Country
Joined: Mar 2018
Posts: 54
Likes: 24
From: Idaho
V10 miss under load
I have a 2000 E 350 with a 6.8 V10. 170K miles.
Under light load/part throttle it misses or surges.
Under heavy load/heavy throttle (like pulling a big hill) it is much more pronounced.
Runs really smooth most of the time. Accelerates smoothly from stop signs.
I replaced the throttle position sensor (new motorcraft part), no improvement.
No codes showing.
I also had lean codes on both banks and changed O2 sensors. That cleared up the codes and check engine light. Before replacing the O2 sensors it ran really rough, wouldn't idle.
Spark plugs and boots have about 10K miles on them. Fuel filter at the same time. I'm pretty careful about gas and run Chevron techron cleaner through it every once in a while.
Stock air intake (not K&N oil type).
No modifications to the intake system, no obvious vacuum leaks.
Any suggestions about tracking this down?
Under light load/part throttle it misses or surges.
Under heavy load/heavy throttle (like pulling a big hill) it is much more pronounced.
Runs really smooth most of the time. Accelerates smoothly from stop signs.
I replaced the throttle position sensor (new motorcraft part), no improvement.
No codes showing.
I also had lean codes on both banks and changed O2 sensors. That cleared up the codes and check engine light. Before replacing the O2 sensors it ran really rough, wouldn't idle.
Spark plugs and boots have about 10K miles on them. Fuel filter at the same time. I'm pretty careful about gas and run Chevron techron cleaner through it every once in a while.
Stock air intake (not K&N oil type).
No modifications to the intake system, no obvious vacuum leaks.
Any suggestions about tracking this down?
Thread Starter
|
Cross-Country
Joined: Mar 2018
Posts: 54
Likes: 24
From: Idaho
Close out on this, I think...
Changed the plugs, replaced 6 coils (cracked), replaced the boots on the coils I reused. All Motorcraft parts.
Started out with a bit of a rough idle, but went for a test drive. Did all the things that used to make it miss, and it didn't. Pulled strong and the rough idle went away after I shut it off and started it again.
Ran a scan, no codes.
It was a bear to get at the center cylinders on both sides, but I think it solved the issue.
Changed the plugs, replaced 6 coils (cracked), replaced the boots on the coils I reused. All Motorcraft parts.
Started out with a bit of a rough idle, but went for a test drive. Did all the things that used to make it miss, and it didn't. Pulled strong and the rough idle went away after I shut it off and started it again.
Ran a scan, no codes.
It was a bear to get at the center cylinders on both sides, but I think it solved the issue.
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Fleet Mechanic
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Nice work. I know it gets expensive changing. Plugs and COPs on a V10. You can learn a lot from a scan tool that can read data. Many use Forscan and/or the Forscan smartphone app. Torque Pro has a paid version for a smartphone that can read many data PIDs. These PID show number of misfires on each cylinder, fuel trims, temperatures and much more. You can catch problems way before a CEL is lit. I just worked on fixing some high fuel trims and it was the MAF. So while a CEL can lead you in the right direction, you need data to confirm the problem and fix.
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