MISFIRE AT TOP SPEEDS

[BEBOP]

I have a 2010 ford sho with 97 thousand plus miles the car runs great at normal speeds but when pressing down on the gas peddle hard to go faster it start to misfire . the car would shake and the service engine light will blink while the car is shaking once the car quite shaking the service engine light would stop blinking and it would have a code that read p301 misfire i change the coil on cylinder 1 plus all the spark plug and i switch the coil from cylinder 1 to cylinder 6 to see would it change firing codes but it didnt it still reading misfire on (i clear the code)cylinder 1 (p301) and i also took it to the dealer and they ran a compression test that pass they also said that all of my fuel injectors were good ... can someone please help me with this problem....... i had seen on youtube pick up trucks that have the eco boost engine was having the same problem and what they did to fix it was made a weep hole in there inter cooler.... do anyone kows this really work ?

 

[SHOdded]

Welcome!

Did you check the plugs/coils yourself? Could be an oil related issue if the injectors are positively verified as good. So the oil would come from either a valve cover gasket leak OR in some cases, too much oil is being carried thru the PCV system and ending in the intercooler, then getting sucked out of the intercooler and into the manifold. Both scenarios have occurred.

First issue - replace gasket. Second issue - install a catchcan and empty it periodically, if there indeed is buildup in the intercooler.

 

[BEBOP]

Yes i change the plugs and also switch coils from cylinder 1 to cylinder 6 and its still saying p0301 i just put on a catch can. should i try empty the intercooler? When i take the car out to test drive it what's happening is when first boost the car runs really great and after maybe around the second time to the third time boosting (meaning going really fast ) thats when the misfire happens and the shaking begins and the engine lights blinking after i let off the gas pedal it and the shaking stop etc..the car gose back to normal at regular speeds ....thank you for helping me trying to figure this thing out ..

 

[SHOdded]

Emptying the intercooler is always a good idea, that way you will keep track of how much crud is ending up in there. May not be contributing to this situation, but cannot hurt.

What oil are you using? How long between oil changes, and what kind of driving (city, mixed, highway)?

It may simply be a case of dirty IAT/MAP sensors, in which case a good cleaning with MAF sensor cleaner or electrical cleaner will take care of it. Rarely, a MAP sensor goes bad, but let's defer that to later.

Which spark plugs did you install? Did you check the plug gaps before installing? 0.030 is the standard gap in a non-tuned SHO. Tuned SHOs will run as low as 0.026. Can you pull that #1 plug and post a hi rez pic of it? Insulator cracking was an issue with the SP528 (the plug originally spec'd for the SHO).

I would at the very least pick up an OBDII scanner and Torque Pro software to monitor and capture datalogs for your SHO. There are plenty of experienced SHO owners here that can read through the datalogs and identify possible issues. You would be monitoring things such as air temp, coolant temp, fuel trims, knock, wastegate duty cycle, throttle position, etc.

BTW, I did not mention injector because the dealership tested them, but that is always in the back of my mind along with compression and spark plug.

 

[BEBOP]

I'm using 5 w 20 motor craft oil, its do for a change i only had the car for about 7 months i dont drive it all the time. ,now the car is letting me know its do for a oil change i'm going to that this week. I have change all the spark plus with auto lite iridium i didnt check the gap because i just brought the 1st stage tune off of livernois and i a assume that they did the gap for me . i also install the 160 thermostat. i have 3 bar map sensor that i didnt install yet because the guy at livernois told to wait to find out was going on before i put a 93 tune on the car and i cant run a 3 bar map sensor without the tune etc..think im going to take back to the dealer for more testing etc. i really believe thats its a injector or that pcv oil is costing all this trouble one or the two. Im going to do what you had told me to do and take pictures of the spark plugs and post on here so that you can see them i cant remember witch is 1 or 2 etc.. thanks again your the best

 

[SHOdded]

Cylinder layout is the same as on the naturally aspirated 3.5
I was not aware that LME sold autolite plugs. If they provided the plugs, they should have gapped them for you, but I would doublecheck.

Knock sensor wiring - since you are checking other things anyway - does not feel like misfire but loss of power. Check to see if it is rubbing against the block, causing false knock readings, causing power to be pulled. Not a common event but not rare either.

 

[BEBOP]

I know that your going to laugh and its okay if you do but were do i find the knock sensor at lol sorry im not a Mechanic but this car is going to make me one lol

 

[SHOdded]

I believe it is near the thermostat housing, will try to find a pic ...

 

[BEBOP]

ok thanks

 

[SHOdded]

https://shoforum.com/index.php?thre...to-your-sho-today.130526/page-25#post-1457419
https://shoforum.com/index.php?threads/inspect-your-wires-for-chaffing.118283/page-3#post-1509429

 

[TonyTheTIger57]

Sounds like a bad injector to me...

 

[BEBOP]

https://shoforum.com/index.php?thre...to-your-sho-today.130526/page-25#post-1457419
https://shoforum.com/index.php?threads/inspect-your-wires-for-chaffing.118283/page-3#post-1509429

https://shoforum.com/index.php?thre...to-your-sho-today.130526/page-25#post-1457419
https://shoforum.com/index.php?threads/inspect-your-wires-for-chaffing.118283/page-3#post-1509429

thank you for the pics and diagram ....

 

[BEBOP]

https://shoforum.com/index.php?thre...to-your-sho-today.130526/page-25#post-1457419
https://shoforum.com/index.php?threads/inspect-your-wires-for-chaffing.118283/page-3#post-1509429

SHOdded do you race your car ? once i get my car running right i would like to . i'm going to make appointment this week at a dealer to get my car checked out to find out on whats going on with etc.. i hope that they dont arm and leg me lol when i had talk to the guy thats works at the dealership he said to him it sound like a inter cooler issue as were oil is going out the turbo etc... i wont keep talking about because the conversation will get old lol but i will let you know on what they say about my car. thanks for all the help.......

 

[SHOdded]

I do not own a SHO, never had anything but Gen 2 SHOs ...

Good luck, I hope you get it figured out pronto.