89 Mustang 5.0 highly modified balks when hot

Ron Fisher · 08-06-2002, 01:25 PM

I've just purchased an 89 Mustang from a guy who rebuilt the motor with a FRPP cam no. E303. It also has Power heads, shorty headers, low restriction exhaust, underdrive, and fuel pressure regulator. The car runs good when it's cold, but as soon as it hits a certain temp. it will balk under a load. At first I thought it was lack of fuel, but when I put in the fuel pressure regulator and adjusted it to 40psi. it didn't make a difference. And after thinking about it, if it runs good when cold, wouldn't that mean it has enough fuel? Anyway, if anyone has an idea why it won't run right, please email me. Thanks.

Skyman · 08-06-2002, 04:13 PM

I would change your o2 sensors, they dont come into play untill the car warms up. And have a lot to do with driveability issues like that.

Skyler

08-06-2002, 01:25 PM	#1
Ron Fisher Registered Member Join Date: Aug 2002 Location: Racine, Wisconsin,USA Posts: 1	89 Mustang 5.0 highly modified balks when hot I've just purchased an 89 Mustang from a guy who rebuilt the motor with a FRPP cam no. E303. It also has Power heads, shorty headers, low restriction exhaust, underdrive, and fuel pressure regulator. The car runs good when it's cold, but as soon as it hits a certain temp. it will balk under a load. At first I thought it was lack of fuel, but when I put in the fuel pressure regulator and adjusted it to 40psi. it didn't make a difference. And after thinking about it, if it runs good when cold, wouldn't that mean it has enough fuel? Anyway, if anyone has an idea why it won't run right, please email me. Thanks. __________________ CorTang Ron

08-06-2002, 04:13 PM	#2
Skyman I need 110mph Trap Speed! Join Date: Feb 1999 Location: So, CA Posts: 4,315	I would change your o2 sensors, they dont come into play untill the car warms up. And have a lot to do with driveability issues like that. Skyler __________________ 2001 BMW M3 6spd 12.79@108 RIP ---- 1993 Notch w/ 98 4V 4.6 Fasttt... -1989 Saleen Mustang #406- 12.32@109 -1999 Black Cobra Coupe- JBA Shorties, Bassani Cat-X, Magnaflow 3", Pulleys, 85mm Pro-M, Ported Intake, Soild Rear w/ 4.30s, Tubular Front End, X2C arms, 13lb batt, few others.

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