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Discussion Starter · #1 ·
Hi All,
I have just been referred to the bard by Bill Jenkins, and have a question... in a few parts.

I have done some mods to my 99 Merc Cougar, 2.5 v6. It now has an AEM short-ram Air intake, a custom Cat-converter by Random Technology, and a dual pipe exhaust by Remus.
At high revs, she does very well, but at low revs and when I put my foot down from an idle, she chokes... like its too much air for her to handle.

Can anybody give me a few options? Mass air flow upgrade? If so, to what?
Thanks in advance.
Brian
 

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chokes like how, not running properly? or just no power?

first thought i had was spark plugs. Check all the couplings on the intake, make sure yr not letting unmetered air in.
 

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What size exhaust system you runnin???
 

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5speed or automatic?
 
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Discussion Starter · #5 ·
Hi Neil,
She chokes like... well I guess you can hear the AEM sucking a lot of air for a brief second and then it comes to an abrupt stop... as if someone put their hand over the intake. ( That is when I am at rest and put my foot down). When I am moving she only likes to accelerate slowly. If I try to get her to race ahead, she almost 'hiccups'. You can feel the gaps in acceleration.
Brian
 

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Many would argue 3" piping is too large for a cat-back. I wouldnt be able to explain how exactly 3" piping would contribute to your symptoms or even if its the cause.

I wonder if your IMRC is closing. Does it feel fine for a while, and then when you get on it once itll accelerate and suddenly be a dog past 3500rpm till you shut the car off and try again?
 
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Discussion Starter · #10 ·
No. exactly the opposite. She chokes low and purrs at high revs. I just replaced the IMRC.
It feels like she isn't getting enough gas or something. Maybe too much air now. How can I retune the CPU to add more fuel... without paying $80/hr to a Ford dealership?!?
 

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ever replaced your fuel filter? :shrug:

I wish i could be more help... i could think of a bunch of things that would contribute to top end loss, not randomized low end loss.
 

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yeah sounds like your MAF is not liking the airflow.

you may have a vacume leak. check all your connections to make sure they are tight. make sure your iat & maf sensors are plugged in.

make sure all the vaccume lines ontop the upper intake manifold are intact.
 
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Discussion Starter · #13 ·
All the MAF sensors are plugged in and there appear to be no leaks. IAT?? Please define.
If it is the MAF, what can I replace it with to work properly?
 

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3" is too large for any N/A 4banger......for a turbo 4 banger it's much different.
 

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Seems to be fuel starvation, but it kinda doesn't make sense if you get good power top end. Replace your fuel filter, its around $10 at a autoparts store. That should help some, especially if your car has never had it replaced.
 
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Discussion Starter · #17 ·
I agree about the fuel starvation, but there's plenty of air: AEM Short Ram intake.
I am leaning towards a 'more fuel (liquid)' solution. But how do I do that? CPU? MAF?
 
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