Flashing check engine light multiple misfire codes

[jp1234]

2015 GT 63k miles 6speed. Hey everyone I was roll racing a buddy today and I was in 4th gear at around 3-3500 rpm and when I floored it, my car didn't really go and had a flashing check engine light that went away after 30s or so. I read the codes and it came back as misfire on cylinder 2,5,6, and 7. And a general misfire code. My car has always had a sort of pulsing idle that makes the car shake a bit but the rpms don't change. Ive changed the plugs about 1k miles ago with Ford OEM plugs all pre gapped. I was wondering if anyone has any idea of something is wrong or if I should of just not floored it at that rpm and gear.

Sponsored

 

[larr12]

Bad gas?

 

[jp1234]

Bad gas?

Could be? I've had the strange idle since I've bought the car but the flashing light was odd

 

[larr12]

Plugs are new so I would check the coils. What gas is/was on the car?

 

[jp1234]

Plugs are new so I would check the coils. What gas is/was on the car?

I use 93, how would I go about checking the coils?

 

[larr12]

Double check the plugs. Mark and move those coils to different cylinders. Also you can turn on the engine and unplug 1 coil at a time and see if there's a change on the idle.

 

[CrackedHorn]

I doubt half your coils went out simultaneously. Especially since both banks are involved.

No misfires until you romped on it?

Pulsing idle could be VVT, purge valve, upstream O2 sensors, weak spark, plugs, coils, vacuum leak or the tune. Could be related to your misfire issue or may not be at all.

What's your tune? How do your fuel trims look? Any parts replaced recently?

 

[jp1234]

Double check the plugs. Mark and move those coils to different cylinders. Also you can turn on the engine and unplug 1 coil at a time and see if there's a change on the idle.

Am I looking for if

I doubt half your coils went out simultaneously. Especially since both banks are involved.

No misfires until you romped on it?

Only the slightly rough idle but even that has never thrown a code. Before this I've never had a code for misfires or anything like it

 

[jp1234]

Double check the plugs. Mark and move those coils to different cylinders. Also you can turn on the engine and unplug 1 coil at a time and see if there's a change on the idle.

Am I looking for if I unplug a coil the idle won't change and that's the bad coil?

 

[CrackedHorn]

Am I looking for if

Only the slightly rough idle but even that has never thrown a code. Before this I've never had a code for misfires or anything like it

Fwiw, my car has idled like that for a long time. (15 GT with manual trans)
Even after cam phasers, chains, solenoids, coils, plugs, etc. I'm replacing O2 sensors today bc they need it and it may fix it. But honestly, I think it's my tune and the car runs fine otherwise and compression is good.

Am I looking for if I unplug a coil the idle won't change and that's the bad coil?

Basically.

However, this test works better when the coil is completely dead vs weak. It's kind of a shade tree way to diagnose.

 

[jp1234]

I doubt half your coils went out simultaneously. Especially since both banks are involved.

No misfires until you romped on it?

Pulsing idle could be VVT, purge valve, upstream O2 sensors, weak spark, plugs, coils, vacuum leak or the tune. Could be related to your misfire issue or may not be at all.

What's your tune? How do your fuel trims look? Any parts replaced recently?

I'm on stock tune, the parts I've replaced recently are the EVAP purge valve because it kept ticking and threw a code eventually so I've changed that twice. Other than that the car is basically stock. How would I look at Fuel trims?

 

[CrackedHorn]

I'm on stock tune, the parts I've replaced recently are the EVAP purge valve because it kept ticking and threw a code eventually so I've changed that twice. Other than that the car is basically stock. How would I look at Fuel trims?

A decent scan tool will show fuel trims. The GSLUIT sc301 scanner cost me $40 and will do this. It shows codes and live data. Though I'm sure there are other scanners around that price as well. I just don't have any experience with them.

 

[jp1234]

A decent scan tool will show fuel trims. The GSLUIT sc301 scanner cost me $40 and will do this. It shows codes and live data. Though I'm sure there are other scanners around that price as well. I just don't have any experience with them.

I got ya I'll look into that. I just took the car for a drive to see if it would act up again, and the cel didn't come on as I was romping on it, so Is it possible that was just a one time thing?

 

[larr12]

Probably a one time thing.

 

[jp1234]

Update: I was driving home last night and my cel started to flash again, this time it ended up staying on and I pulled the code p0300

Sponsored