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Hesitation when cold

7K views 16 replies 9 participants last post by  tc x 4 
#1 ·
Hi everyone. First post about the Roush Mustang I just purchased. Not sure if this is an issue but figured this would be the place to ask.

When I first start my car and put it into gear (5 speed) I have noticed that it feels like it bogs down and doesnt want to go right away. It takes about 2 seconds to catch up with it self and drives normal until I either slow back down or switch gears, then it does the same thing. When the car reaches normal operating temps it has no issues and has from what I can tell all the power it is supposed to have. Is that just what it is with cars like these? Not sure if you can tell what type of car it is so..... 2007 Mustang 427R. Enough said?
 
#6 ·
My 07 mustang bucks alot cold, but goes away after driving 1-2 mins, my girlfriend always complains about me letting the car warm up, but you try explaining why, it's like explaining calculus to a donkey
 
#10 ·
on my old pre 05 the IAC (idle bypass valve) would go bad and it would act up worse when cold as it controls the idle of the car and didnt work as good when cold vs warmed up. It could be that.

If I remember right ht 427 has the same basic engine as the Gt, cant remember if it has a supercharger on top or not, regardless it has the same valve somewhere.
 
#14 ·
I dont really know what you would consider stock. My version of stock is what I have which is the 4.6L with a 2.3L M90 Supercharger. Im pretty sure from the way it acts, and the suggestions that everyone has given me, that it is a normal thing for a car like that. My idle speed is right around 700-750.
 
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