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Car Ran Terrible Tonight :(

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50hhh

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. Check your air box, filter, and snorkel (rear of grille) for obstructions as it sounds akin to an induction system issue (sounds like whatever it is its before it hits the Mass Airflow Sensor)
This could be it I'll have to pull the filter and snorke and take a look.
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ConspicuousConsumption

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lol I wasn't getting beat I was just comparing it to a 3v 4.6 that I drove for many years. I didn't really get beat in that car either.
I've read a lot of guys on here saying that the S550 doesn't feel as "brutal" as past Mustangs, even the S197. Maybe it just feels more refined and less rough, therefore sluggish in comparison? Sorry for saying you got beat etc :)
 
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I've read a lot of guys on here saying that the S550 doesn't feel as "brutal" as past Mustangs, even the S197. Maybe it just feels more refined and less rough, therefore sluggish in comparison? Sorry for saying you got beat etc :)
I see but Ive had the car for 5 months and had another 5.0 before this so I know how it USED to run. This is more about the last two weeks.
 

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Human perception is notoriously unreliable. You'll need some data points if your induction system checks out okay and you still feel the car is sluggish.
 

ConspicuousConsumption

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I see but Ive had the car for 5 months and had another 5.0 before this so I know how it USED to run. This is more about the last two weeks.
Pretty interesting and unfortunate. Winter blend fuel out already maybe?
 

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hemistar1

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Years of Driving

The butt dyno isnt reliable. Use gps and run some times. Just because you're getting beat by cars you think should be slow doesn't mean your car is broken. Also check the driver mod.
I agree with CC

Do the small things 1st ... disconnect the battery then reconnect ( should clear memory and rest preliminary routines )check the air box , full it with different gas 87 is okay to use,listen for sounds when shifting ... change the oil if its time...check to make sure 8 qts.. take it to dealer for a diagnostic if it still does feel right.

Do the harder things next .. take it to track and baseline it ..make 2 or 3 passes. Wait a week and then take it back ,,, If you get the same times you are okay..

The seat of your pants feel is subjective but after years of driving you can get a feel for how fast you should be but the scientific ( the track) is the best objective judge.

If all else fails ...start saving for that Shelby GT350-----just kiddding!

Good luck and let us know how this turns out!:ford:
 
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50hhh

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I agree with CC

Do the small things 1st ... disconnect the battery then reconnect ( should clear memory and rest preliminary routines )check the air box , full it with different gas 87 is okay to use,listen for sounds when shifting ... change the oil if its time...check to make sure 8 qts.. take it to dealer for a diagnostic if it still does feel right.

Do the harder things next .. take it to track and baseline it ..make 2 or 3 passes. Wait a week and then take it back ,,, If you get the same times you are okay..

The seat of your pants feel is subjective but after years of driving you can get a feel for how fast you should be but the scientific ( the track) is the best objective judge.

If all else fails ...start saving for that Shelby GT350-----just kiddding!

Good luck and let us know how this turns out!:ford:
Very good suggestions! I had heard of people doing ECU resets on 91 and getting good results.
 

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If you can, drive another car for a couple days. A four cylinder or an SUV would be great. That'll reset your butt dyno and your GT will feel like a rocket again.

:thumbsup:

P.S. I used to ride sportbikes that would destroy our cars and somedays even they felt "slow".
 

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87 cuts timing vs 93 octane, 380 hp vs 435 hp. stop and go traffic and hotter motor

dirty air filter? bad spark plug, mind?

or heck maybe the motor goes boom
 

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87 cuts timing vs 93 octane, 380 hp vs 435 hp.
No. Ford as claimed there is like a 1% power loss on 87 vs. 91 on the 5.0. I think you are thinking ecoboost and its 13% loss.
 
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No. Ford as claimed there is like a 1% power loss on 87 vs. 91 on the 5.0. I think you are thinking ecoboost and its 13% loss.
I Have ran my 2011 5.0 on a dyno a couple times and always noted a 10hp difference from 87 to 91/93. With the new motor I would expect a larger gap based on the fuel.
 

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There are zero issues running 87 and savings aren't marginal at all.
Sure there is an issue, as he is stating a loss of power/feel and is running a mix of 87. The savings of running 87 vs 91/93 is roughly $4.00-$5.00 per fill up. To me that is "marginal" considering the relative cost of the car.

We all know that there are also variations in the quality of fuel, and my guess is that it fluctuates greater at the 87 octane level compared to 91/93. So in theory, if he got a bad tank of 87, the car will make necessary changes to accommodate for the poor fuel and may be noticeable as the OP stated.


has nothing to do with 87, get out of here with that. seriously.
I was simply stating that it may be an issue, and the car does run differently on the 87 of which the OP is posting about. Have you tested his fuel and ruled that out as being a factor in the issue? With no codes present, what is your theory?

Do you run 87 in yours?
 

foghat

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I Have ran my 2011 5.0 on a dyno a couple times and always noted a 10hp difference from 87 to 91/93. With the new motor I would expect a larger gap based on the fuel.

Same day, same dyno? If not, pretty hard to state anything conclusive on a 10hp delta. You could see that on different days even with everything on the car being identical.

Then, if you assume Ford is telling the truth, that 1% diff is about 4hp, factor that into your 10hp and now you have only a 6hp difference - which could easily be attributed to different days/different conditions. It is not uncommon to see 4-6hp deltas on the same day same dyno with no changes to car.

Either way, the difference is nowhere near the 55hp that was stated and to which I was initially replying.
 
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Sure there is an issue, as he is stating a loss of power/feel and is running a mix of 87. The savings of running 87 vs 91/93 is roughly $4.00-$5.00 per fill up. To me that is "marginal" considering the relative cost of the car.

We all know that there are also variations in the quality of fuel, and my guess is that it fluctuates greater at the 87 octane level compared to 91/93. So in theory, if he got a bad tank of 87, the car will make necessary changes to accommodate for the poor fuel and may be noticeable as the OP stated.




I was simply stating that it may be an issue, and the car does run differently on the 87 of which the OP is posting about. Have you tested his fuel and ruled that out as being a factor in the issue? With no codes present, what is your theory?

Do you run 87 in yours?
I agree with the 91 advantage I have seen the difference in RWHP myself. Ford rates the car at 87 for marketing reasons only. Theres no denying this motor is made for 91+. Doesn't the Boss run 91? And this new motor is much closer to it than the pre 2015 5.0. What I did last night is put half a tank of 93 on top of the 1/4 tank of 87 and no difference.
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