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Discussion Starter · #1 ·
I stopped at a mobil and put 10 dollars 93 in the tank, about 15 min later driving on highway i went to accelerate and it starts stumbling like a misfire. Very light throttle its fine but as soon as you give it a little gas it will shake and stumble. at idle it sounds like a misfire and engine runs rough.

I checked the intercooler hoses and everything seems connected. i tried scanning engine with cobb tuner and didnt get any codes.
I flashed it to cobb stage one 87 octane and it seemed the same.

should i drive it or let it idle for a code to pop up?
should i scan it with my scangauge?
should i pull the plugs and check them? they have about 20k.
should i add octane booster?

44k stage one
fswerks intake
mbrp catback
one step colder plugs
stratified 93 tune.

car was parked at work over the weekend as to i did not want to risk anything happening as to my commute is 45 min.
 

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I stopped at a mobil and put 10 dollars 93 in the tank, about 15 min later driving on highway i went to accelerate and it starts stumbling like a misfire. Very light throttle its fine but as soon as you give it a little gas it will shake and stumble. at idle it sounds like a misfire and engine runs rough.

I checked the intercooler hoses and everything seems connected. i tried scanning engine with cobb tuner and didnt get any codes.
I flashed it to cobb stage one 87 octane and it seemed the same.

should i drive it or let it idle for a code to pop up?
should i scan it with my scangauge?
should i pull the plugs and check them? they have about 20k.
should i add octane booster?

44k stage one
fswerks intake
mbrp catback
one step colder plugs
stratified 93 tune.

car was parked at work over the weekend as to i did not want to risk anything happening as to my commute is 45 min.
I'd check the plugs first, easiest thing to do. It'll take 15 min.
 
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Bad gas. I would baby it until its time for a fill up. I wouldn't bother trying to chase down any other possible issues until you run through this tank of gas.
 

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Discussion Starter · #4 ·
Thanks for the insight. Ended up being bad plugs. All of them were gapped at .040 instead of .026. Had about 20k on them. had denso's replaced with ngk's

i added some octane booster while i was changing the plugs just to be safe

It runs and idles perfect again.
 

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This car is so susceptible to bad plugs/bad gaps. It's totally worth inspecting the plugs/gaps at every OCI.
 

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2017 Ford Fusion Sport
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8,198 Posts
This car is so susceptible to bad plugs/bad gaps. It's totally worth inspecting the plugs/gaps at every OCI.
Still waiting on mine...last time I order something that isn't a prime item on Amazon lol my car is running like absolute donkey sheet. Where those new ones @ tho :rolleyes:
 
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