I need help, I have a 2010 ford Taurus sho, I have had it for almost 2 months. This issue started about 4 days ago. I had a constant misfire in cylinder 3, I had a smoke coming from my exhaust, at first I had thought it was spark plugs so I swapped those, then I swapped the ignition coils with a neighboring cylinder and the misfire didn’t jump, then I thought it was the gaskets on the valve cover, we swapped those and no help, then we thought it was a intake manifold gasket issue, we swapped the gaskets and cleaned the carbon out of there. We let it run for a while and drove a bit, but nothing helped. We also added in fuel injector cleaner but that didn’t help. It has stayed on cylinder 3 and not moved or anything. I have a foxwell obd2 port scanner so if anyone has any suggestions on what this could be please let me know along with how to figure out if that is the culprit. Thank you!
SHO engine troubles
- Thread starter GreenEcko
- Start date
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Miles? Just a WAG, injector(s) stuck open. Damaged #3 piston. Test compression and leakdown on all cylinders. Use a scan tool to monitor high pressure fuel desired and actual, which will tell if an injector is stuck open.
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well looks like a fuel injector, u never posted miles, any maintenance history you have or paid for?
142000 miles, I haven’t paid for any other maitinence besides the parts I replaced in the thread above.
my best suggestion its time for a history report, this car will need a water pump and every fluid changed on top of replacing every injector. you never want to do one at this point.
Junkyard_Mad-Scientist
SHO Member
As others have said it sounds like an injector, I chased this phantom myself last year. Go ahead and replace all 6, even if the issue persists these cars need them at some point and based on your miles you're probably due. Plus with the symptoms you have and other things you've already ruled out its a pretty good bet. As for the white smoke, could be unrelated and just oil in the system somewhere or turbo seals, does your car have a catch can? You can also do as @kryptto suggested and get a vehicle history report, I'd start by calling Ford and seeing what records are available from them, some shops will report major repairs but unless you can contact the previous owner it may be difficult to get good records outside the dealer. If you cant confirm that the water pump and/or timing chains have been dealt with then I would start a piggy bank now. Also, I would service the Trans, PTU, RDU if you haven't already as it wasn't until recently Ford started servicing them prior to which they considered them to have lifetime fluids and it wasn't considered a serviceable part
You don't need to read the whole thread however as entertaining as it is but read the maintenance bible as written by our eldest members;
Thread 'SM105K's Ownership/Performance/Maintenance Thread' https://shoforum.com/threads/sm105ks-ownership-performance-maintenance-thread.138235/
Thread 'SM105K's Ownership/Performance/Maintenance Thread' https://shoforum.com/threads/sm105ks-ownership-performance-maintenance-thread.138235/
SM105K
Streetlight Grand Prix Champ/ IG @fafomotorsports
Ha the first couple of pages are good. Then it goes 97 different ways with 5 other vehicles.....
Junkyard_Mad-Scientist
SHO Member
are we including the 450 and the unimog? Unimog counts at this point considering how many times I referenced it
Axle
New Member
When having issues such at this. The first thing I would do is a compression test of all cylinders. Without proper compression, nothing else matters. Be sure to document what the pressure are on each cylinder.
I am not familiar with the engine in a 2010. Does the engine have Direct Injection. Do the injectors fire fuel directly into the cylinders. If so, you need to consider what is happening with the PCV circuit. The PCV valve dumps oil vapors into the intake manifold. In early designs, the fuel fired into the intake manifold would wash that oil off the intake valves. In a direct injection engine. That doesn't happen and the intake valves tend to get gunked up with this oil and later will fowl the valves with a build up of crude.
It sounds to me like you have a compression issue or a blown head gasket. Or fowled intake valves. Although, with fowled intake valves. There would be other problems such as backfires in the intake manifold. Other issues with the valve train are possible. When doing the compression test. Be sure to do a Leak Down test. See if the cylinder holds compression.
luigisho
SHO Member
All really good 1st guess replies in this thread. I think white smoke can also indicate stuck open injector. So wet plug and white smoke can be coolant or fuel. If you have spark (good plug and coil fire) and good compression (do leakdown and compression as Texas M already stated)-- and spark plug is wet, probably injector. Does the exhaust smell like excessive fuel? Does the injector on the faulty cylinder have inconsistent sound or feel compared to other injectors firing? You can try to get a pressure gauge on the fuel schrader valve, let the car run a little, turn it off and see if the system holds pressure for a couple 3-4 minutes. An open injector can leak pressure down far more quickly than normal. OR you can remove the fuel rail with injectors attached, turn the key to on (not run or whatever is says to start the car) which primes the fuel system, and often you can see the injector leaking.
Unfortunately, that is not an option on the 3.5 Ecoboost. No schrader valve and removing the rail and injectors involves removing the intake manifold first. You are also dealing with very high pressure to the injectors. But, you can monitor that with a scan tool. High pressure fuel desired and high pressure fuel actual.
Thanks everyone for all the replies. I'm the OP's dad who has been working with him with this. He's 16, this is his first car and this is our first Taurus SHO. It's been a learning experience so far in the short time we've had it. I give him a lot of credit for making an account here and reaching out to you all for pointers and help. I didn't expect I would be working with him on partial engine disassembly for his first car a few months in. It was supposed to be oil changes and plugs as needed. 
I have a Foxwell scan tool and have some data stored from some of our scans. We're going to pick up a scope for the cylinder and a compression testing kit for additional tests. I want to say from memory the high pressure fuel desired and actual were close to the same values and one of the banks had a different long term fuel trim value that coincided with the misfiring bank.
We'll look into a few more things and report back. Really hoping it's not a head gasket as I have the service manual and opening it up that much is going to suck considering how much teardown we will need to do.
Maint History
Someone asked about maintenance history, we did get that when we bought it and it was running great up to a week ago. I'll summarize what we know has been done.
It appears to have regular oil and filter change records along the way but here are some of the other items.
06/2015 55k miles - new plugs, trans fluid flushed.
12/2015 59k miles - antifreeze/coolant flushed/changed, thermostat housing/gasket replaced
04/2016 63k miles - new plugs
08/2017 79k miles - new plugs
07/2020 108k miles - new plugs
06/2023 122k miles - A/C recharge, New Alternator, rear shock absorbers
03/2024 -~123k miles - Differential Fluid Flushed/changed, rear diff serviced, trans fluid flushed, valve cover gaskets replaced.
04/2025 140k miles - (This is when we bought it) Oil and Filter, O2 sensor replaced, rear diff pinion seal replaced, new plugs.
We haven't owned it long, it has a K&N Air Raid filter and open top box, Magnaflow exhaust but no idea if there was any attempts at a tune in the past.
Recent history and what we've tried/done so far.
This isn't the first misfire issue, but they were appearing on the other bank and it was sporadic and those went away. We've swapped COP's around but haven't replaced them. On the right side we found some oil around the plug well at the seal on Cyl 1 and 3. We replaced the valve cover gasket and installed new seals as well as new boots and seals for the COP's all around. It's got new plugs now all around. Originally we removed the intake manifold to get to the injectors and when we removed it we found what appeared to be bad gaskets on the coolant channels. When it was removed we also noted liquid in with cylinder 3's valve which I had assumed was from a bad gasket on the intake manifold. Those were cleaned out with the valves fully closed and dry when we reassembled.
No leaks under the car that we have ever noticed and the coolant looked clean/normal when we drained it for the intake manifold. We also changed the oil after the recent repairs and it appeared normal with no signs of coolant mixed in. Inspected the wiring harness connector for cyl 3's coil and didn't see any wear or obvious wire issues.
So, we'll get a compression test and try and scope the cylinder for more info and try and narrow it down from here. The foxwell scanner is pretty new for me and I understand what most of the values are but the tips about checking long term fuel trim give us something to report back.
On the scans it shows the acceleration value of each cylinder and 1, 2, 4, 5, and 6 all have values around 0 that fluctuates, Cyl 3 fluctuates around -1 to -2. I am not sure what that's indicative of and haven't found a good breakdown or explanation.
I have a Foxwell scan tool and have some data stored from some of our scans. We're going to pick up a scope for the cylinder and a compression testing kit for additional tests. I want to say from memory the high pressure fuel desired and actual were close to the same values and one of the banks had a different long term fuel trim value that coincided with the misfiring bank.
We'll look into a few more things and report back. Really hoping it's not a head gasket as I have the service manual and opening it up that much is going to suck considering how much teardown we will need to do.
Maint History
Someone asked about maintenance history, we did get that when we bought it and it was running great up to a week ago. I'll summarize what we know has been done.
It appears to have regular oil and filter change records along the way but here are some of the other items.
06/2015 55k miles - new plugs, trans fluid flushed.
12/2015 59k miles - antifreeze/coolant flushed/changed, thermostat housing/gasket replaced
04/2016 63k miles - new plugs
08/2017 79k miles - new plugs
07/2020 108k miles - new plugs
06/2023 122k miles - A/C recharge, New Alternator, rear shock absorbers
03/2024 -~123k miles - Differential Fluid Flushed/changed, rear diff serviced, trans fluid flushed, valve cover gaskets replaced.
04/2025 140k miles - (This is when we bought it) Oil and Filter, O2 sensor replaced, rear diff pinion seal replaced, new plugs.
We haven't owned it long, it has a K&N Air Raid filter and open top box, Magnaflow exhaust but no idea if there was any attempts at a tune in the past.
Recent history and what we've tried/done so far.
This isn't the first misfire issue, but they were appearing on the other bank and it was sporadic and those went away. We've swapped COP's around but haven't replaced them. On the right side we found some oil around the plug well at the seal on Cyl 1 and 3. We replaced the valve cover gasket and installed new seals as well as new boots and seals for the COP's all around. It's got new plugs now all around. Originally we removed the intake manifold to get to the injectors and when we removed it we found what appeared to be bad gaskets on the coolant channels. When it was removed we also noted liquid in with cylinder 3's valve which I had assumed was from a bad gasket on the intake manifold. Those were cleaned out with the valves fully closed and dry when we reassembled.
No leaks under the car that we have ever noticed and the coolant looked clean/normal when we drained it for the intake manifold. We also changed the oil after the recent repairs and it appeared normal with no signs of coolant mixed in. Inspected the wiring harness connector for cyl 3's coil and didn't see any wear or obvious wire issues.
So, we'll get a compression test and try and scope the cylinder for more info and try and narrow it down from here. The foxwell scanner is pretty new for me and I understand what most of the values are but the tips about checking long term fuel trim give us something to report back.
On the scans it shows the acceleration value of each cylinder and 1, 2, 4, 5, and 6 all have values around 0 that fluctuates, Cyl 3 fluctuates around -1 to -2. I am not sure what that's indicative of and haven't found a good breakdown or explanation.
Junkyard_Mad-Scientist
SHO Member
Make sure you and your son hit the intro page for a proper welcoming if you haven't done so. I must warn and I believe several others will agree that this car is not light maintenance. No better crash course on vehicle work for sure but they are needy and finikie. I noticed the PTU has not been serviced by your records and that is a major fail point on these cars, much more common than head gaskets. But one thing at a time right? I can't say with certainty what those readings mean but I can share my experience.
I had a random misfire that I chased and performed much of the same procedures you and your son have done to no avail. I closely monitored my fuel with forscan while driving and caught it in the act which pointed me to injector. I was urged to get oem since its a task to get to the injectors but ended up getting standards, remfg Bosch. The fuel rail is connected for both banks, which means a low pressure condition can be difficult to diagnose, my leaking injector was causing both banks to show low pressure since it was dumping into the cylinder. After doing it twice I had a full set of new injectors and my misfire and other mild oddities went away including long cranking.
If I had to put money on it I'm going injectors. A leak down test won't hurt and its a good teaching point for your boy, not sure if I would go as far as scoping the cylinder if the test came back okay but that's me.
You will learn a lot on this forum, its the best car community out there with the best people. Good luck, we're all here if you need help
I had a random misfire that I chased and performed much of the same procedures you and your son have done to no avail. I closely monitored my fuel with forscan while driving and caught it in the act which pointed me to injector. I was urged to get oem since its a task to get to the injectors but ended up getting standards, remfg Bosch. The fuel rail is connected for both banks, which means a low pressure condition can be difficult to diagnose, my leaking injector was causing both banks to show low pressure since it was dumping into the cylinder. After doing it twice I had a full set of new injectors and my misfire and other mild oddities went away including long cranking.
If I had to put money on it I'm going injectors. A leak down test won't hurt and its a good teaching point for your boy, not sure if I would go as far as scoping the cylinder if the test came back okay but that's me.
You will learn a lot on this forum, its the best car community out there with the best people. Good luck, we're all here if you need help
A borescope would be a quick way to check for piston damage and possibly a leaking head gasket. Apply pressure to the coolant reservoir, max 20 psi, and look for seepage in the cylinder.
Another clue to a leaking head gasket is that the piston is cleaner than the others. Water makes steam, steam cleans the piston.
Another clue to a leaking head gasket is that the piston is cleaner than the others. Water makes steam, steam cleans the piston.
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luigisho
SHO Member
Well, welcome. This is the place where people come because they bought a car that has been forcing people to become backyard mechanics since 1989. These cars have always been maintenance pigs. The new ecoboost even more so. awd, twin turbo with its high and low pressure fuel pumps and direct injection, modern electronics that are very sensitive to voltage, etc. Post updates. It helps when others have similar issues to have it archived here.Thanks everyone for all the replies. I'm the OP's dad who has been working with him with this. He's 16, this is his first car and this is our first Taurus SHO. It's been a learning experience so far in the short time we've had it. I give him a lot of credit for making an account here and reaching out to you all for pointers and help. I didn't expect I would be working with him on partial engine disassembly for his first car a few months in. It was supposed to be oil changes and plugs as needed.
Junkyard_Mad-Scientist
SHO Member
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