Only 75% Power When Hot

Calebnc302

New Member
Apr 29, 2013
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My 03 gt 5spd with nitto 555s will throw u in the back seat at WOT after a easy 2 or3 minute warmup to about half way to operating temp. But once it gets hot then it has this lack of accelerating like it stays in lower Rpms for a longer period. It's like it lost 20% power. I have replaced fuel filter, plugs, air filter, cleaned maf. It runs good, no sputter, or cutting out, it just loses acceleration. Also no cel or codes. Could the heat affect it this much? If so, what can help this?
 
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trinity_gt

10 Year Member
Jan 31, 2003
3,125
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Canada
Do you have an aftermarket intake on the car? If so, what type?

Theory: A cone filter open to the engine bay is sucking hot, underhood air. High IATs result in less dense air and retarded timing to prevent detonation.
 

Calebnc302

New Member
Apr 29, 2013
27
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2
Yeah I'm pretty sure I'm losing more than I should be when it's hot. I'm prolly exaggerating with 25% but its definitely noticeable loss of acceleration. What could be wrong?
 

Calebnc302

New Member
Apr 29, 2013
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Hey Trinity gt my car does not have the air silencer/snorkel. I was mistaken about this. Do u think this could be my problem on a warm day sucking in more heat? Like I swear it feels like I lose 20hp maybe more when it's hot.
 

trinity_gt

10 Year Member
Jan 31, 2003
3,125
80
99
Canada
Hey Trinity gt my car does not have the air silencer/snorkel. I was mistaken about this. Do u think this could be my problem on a warm day sucking in more heat? Like I swear it feels like I lose 20hp maybe more when it's hot.

Without the snorkel the engine is pulling air from the under-hood environment through the big hole in the side of the airbox. If you have high under-hood temperatures you're losing charge density and the PCM is probably pulling spark timing. I think the factory tune is pretty mild when it comes to timing and IATs because the 2V lacks knock sensors and is factory-rated to run with 87-octane fuel.

See what you can do to get cool air from the fenderwell and see if that makes a difference.
 

Mustang5L5

That is…until I whipped out my Bissell
Mod Dude
Feb 18, 2001
40,018
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Massachusetts
My 03GT i bought brandy new was a dog when it was hot. Toss the A/C on and it felt completely gutless. I've never had a car with as much power loss when it was 90+ degrees out as that one.
 
I might be misunderstanding what you're reffering to... do you have problems at car op temps or outside weather temps? Don't rule out internal problems if its not extreamly hot outside. Last summer at the track temps were over 100 degrees and i had no performance issues. Do this test... next time youre on the freeway and you feel your car is doing what you explained above, once you've shifted into 3rd and you're at wot... back off the throttle just a touch...say 3/4 throttle. If your rpm jump up in any way have your ride checked for compression and valve accuracy.