Weird stumble when at WOT
 

Hey guys,

I am getting a weird stumble from my 1990 GT when I mash down the
pedal at WOT. It feels like all of a sudden I am running out of gas
or just loosing power. I have checked all the vacuum lines and I am
not sure what else could be causing this. Here are the modifications
I have done recently which one of has to have caused this:

Cobra upper and lower intake manifold (w/spacer)
Shorty headers
Radiator
Water pump
Fan w/clutch and shroud
cap and rotor
wires
alternator (upgrade to 130A)
Ram air hood

If anyone has any idea what could be causing this I would appreciate
this, it's not fun when your mustang won't get up and go when you want
it to. Thanks for the help guys.

Sean

Weird stumble when at WOT
 

Had the same problem many years ago... accelerated great, except at WOT.
I'm going to bet it's electrical. I would for sure check the plugs, wires,
etc. (bad wire, misgapped plugs).

Brad


"GT5OH" > wrote in message
...
> Hey guys,
>
> I am getting a weird stumble from my 1990 GT when I mash down the
> pedal at WOT. It feels like all of a sudden I am running out of gas
> or just loosing power. I have checked all the vacuum lines and I am
> not sure what else could be causing this. Here are the modifications
> I have done recently which one of has to have caused this:
>
> Cobra upper and lower intake manifold (w/spacer)
> Shorty headers
> Radiator
> Water pump
> Fan w/clutch and shroud
> cap and rotor
> wires
> alternator (upgrade to 130A)
> Ram air hood
>
> If anyone has any idea what could be causing this I would appreciate
> this, it's not fun when your mustang won't get up and go when you want
> it to. Thanks for the help guys.
>
> Sean

Weird stumble when at WOT
 

"GT5OH" > wrote in message
...
> Hey guys,
>
> I am getting a weird stumble from my 1990 GT when I mash down the
> pedal at WOT. It feels like all of a sudden I am running out of gas
> or just loosing power. I have checked all the vacuum lines and I am
> not sure what else could be causing this. Here are the modifications
> I have done recently which one of has to have caused this:
>
> Cobra upper and lower intake manifold (w/spacer)
> Shorty headers
> Radiator
> Water pump
> Fan w/clutch and shroud
> cap and rotor
> wires
> alternator (upgrade to 130A)
> Ram air hood
>
> If anyone has any idea what could be causing this I would appreciate
> this, it's not fun when your mustang won't get up and go when you want
> it to. Thanks for the help guys.
>
> Sean

could also b a plugged converter

Weird stumble when at WOT
 

GT5OH wrote:
> Hey guys,
>
> I am getting a weird stumble from my 1990 GT when I mash down the
> pedal at WOT. It feels like all of a sudden I am running out of gas
> or just loosing power. I have checked all the vacuum lines and I am
> not sure what else could be causing this. Here are the modifications
> I have done recently which one of has to have caused this:
>
> Cobra upper and lower intake manifold (w/spacer)
> Shorty headers
> Radiator
> Water pump
> Fan w/clutch and shroud
> cap and rotor
> wires
> alternator (upgrade to 130A)
> Ram air hood
>
> If anyone has any idea what could be causing this I would appreciate
> this, it's not fun when your mustang won't get up and go when you want
> it to. Thanks for the help guys.
>
> Sean

Have you checked the fuel filter? It could be clogged.
--
Cheers, Bob

Weird stumble when at WOT
 

Bob Willard wrote:
> GT5OH wrote:
>> Hey guys,
>>
>> I am getting a weird stumble from my 1990 GT when I mash down the
>> pedal at WOT. It feels like all of a sudden I am running out of gas
>> or just loosing power. I have checked all the vacuum lines and I am
>> not sure what else could be causing this. Here are the modifications
>> I have done recently which one of has to have caused this:
>>
>> Cobra upper and lower intake manifold (w/spacer)
>> Shorty headers
>> Radiator
>> Water pump
>> Fan w/clutch and shroud
>> cap and rotor
>> wires
>> alternator (upgrade to 130A)
>> Ram air hood
>>
>> If anyone has any idea what could be causing this I would appreciate
>> this, it's not fun when your mustang won't get up and go when you want
>> it to. Thanks for the help guys.
>>
>> Sean
>
> Have you checked the fuel filter? It could be clogged.

It might be a dying fuel pump too. My guess is the problem is fuel related.

Weird stumble when at WOT
 

On Jul 12, 6:04 am, Michael Johnson > wrote:
> Bob Willard wrote:
> > GT5OH wrote:
> >> Hey guys,
>
> >> I am getting a weird stumble from my 1990 GT when I mash down the
> >> pedal at WOT. It feels like all of a sudden I am running out of gas
> >> or just loosing power. I have checked all the vacuum lines and I am
> >> not sure what else could be causing this. Here are the modifications
> >> I have done recently which one of has to have caused this:
>
> >> Cobra upper and lower intake manifold (w/spacer)
> >> Shorty headers
> >> Radiator
> >> Water pump
> >> Fan w/clutch and shroud
> >> cap and rotor
> >> wires
> >> alternator (upgrade to 130A)
> >> Ram air hood
>
> >> If anyone has any idea what could be causing this I would appreciate
> >> this, it's not fun when your mustang won't get up and go when you want
> >> it to. Thanks for the help guys.
>
> >> Sean
>
> > Have you checked the fuel filter? It could be clogged.
>
> It might be a dying fuel pump too. My guess is the problem is fuel related.

That is what my guess was too. I am going to replace the fuel pump
with a better flowing unit and replace the fuel filter while i'm at
it. I am going to have to post some pics for you guys she's lookin'
pretty sweet with that new ram air hood. :-) Thanks for the input
guys.

Sean

Weird stumble when at WOT
 

GT5OH wrote:
> Hey guys,
>
> I am getting a weird stumble from my 1990 GT when I mash down the
> pedal at WOT. It feels like all of a sudden I am running out of gas
> or just loosing power. I have checked all the vacuum lines and I am
> not sure what else could be causing this. Here are the modifications
> I have done recently which one of has to have caused this:
>
> Cobra upper and lower intake manifold (w/spacer)
> Shorty headers
> Radiator
> Water pump
> Fan w/clutch and shroud
> cap and rotor
> wires
> alternator (upgrade to 130A)
> Ram air hood
>
> If anyone has any idea what could be causing this I would appreciate
> this, it's not fun when your mustang won't get up and go when you want
> it to. Thanks for the help guys.
>
> Sean

I'd check your fuel pressure. I believe it should be somewhere around
45 psi. Might want to check your manual on that one. Replace your fuel
filter, if you haven't lately. Also, Check resistance in your spark
plug wires.