5.0 Cuts out over 5,000 RPM??

[allballsmustang]

I have an 89 GT 5.0. Having a problem with it cutting out over 5 grand. Anyone have a similar problem? Mods are as follows: Mac cold air intake, underdrive pulleys, shorty headers, off road h pipe and flowmaster cat back.
I've replaced many other things as well with stock parts. Id appreciate anyones help or anyone that knows of a motorsports shop in my area, im in eastern PA. Thanks.

Jim

 

[Quijibow_69]

Where exactly in Eastern PA are you from?

 

[allballsmustang]

Where exactly in Eastern PA are you from?

I'm from Mount Bethel. It's about 10 miles south of Stroudsburg if you know where that is...

 

[The Fox]

What fuel mods have you done? Consider fuel pump, MAS, TB, injectors, rockers not on pushrod 100%? Could be a lot of things. Need more info.

Anthony

 

[Jekyl]

I have an 89 GT 5.0. Having a problem with it cutting out over 5 grand. Anyone have a similar problem? Mods are as follows: Mac cold air intake, underdrive pulleys, shorty headers, off road h pipe and flowmaster cat back.
I've replaced many other things as well with stock parts. Id appreciate anyones help or anyone that knows of a motorsports shop in my area, im in eastern PA. Thanks.

Jim

I have the same car as you and the same mods as you. I find that my car loses power considerably after 4800 rpm.... I read that I should be shifting at 5200 rpm but it feels like it lost power at around 4700-4900 ...... So If thats what you mean by cutting out then .....yeah It might be normal..unless I have a problem as well.

 

[Quijibow_69]

I've heard of Stroudsberg...how close to Harrisburg are you? There is www.cjponyparts.com in Harrisburg and www.mcnewsautomotive.com in Dillsburg. Those are the only shops I know of, they are near Harrisburg.

 

[allballsmustang]

I have the same car as you and the same mods as you. I find that my car loses power considerably after 4800 rpm.... I read that I should be shifting at 5200 rpm but it feels like it lost power at around 4700-4900 ...... So If thats what you mean by cutting out then .....yeah It might be normal..unless I have a problem as well.

Yeah thats exactly whats happening with mine as well but i dont see any reason for it not to be able to get up to redline.

 

[allballsmustang]

What fuel mods have you done? Consider fuel pump, MAS, TB, injectors, rockers not on pushrod 100%? Could be a lot of things. Need more info.

Anthony

I have a new fuel pump(stock)and new MAS(stock). When im driving it feels like it cuts short on fuel but its hard to tell...i tested pressure on it when its idling and its ok...but its kinda hard to check while driving...

Jim

 

[allballsmustang]

I've heard of Stroudsberg...how close to Harrisburg are you? There is www.cjponyparts.com in Harrisburg and www.mcnewsautomotive.com in Dillsburg. Those are the only shops I know of, they are near Harrisburg.

I've been to Dillsburg...actually to a stang shop called Kauffman Motorsports...but thats pretty far for me...bout 2 hours atleast..

 

[Kerpal]

When's the last time you did a full tune up? If your ignition parts are getting old power will drop off quickly at higher RPM.

 

[HISSIN50]

plug type and gap?

 

[allballsmustang]

The wires are new. There accel 8mm. Plugs are new Accel U-Grooves. New Accel performance cap and rotor. Ignition Coil isnt new but its a Accel Super Coil. I think the gap was 35 thousandth, i dont remember...

 

[HISSIN50]

ok, plat plugs can cause a high speed misfire for some. and a weak coil can cause a miss at higher rpms (often, reducing the plug gap helps with that, but you have a narrow gap as it is - why so narrow, BTW?). and you are sure the plug wires are not near each other (misfire through the wires at high rpms)?

this is just random stuff that is coming to mind. good luck.