Speedo waaaay off

[Big E 4]

I'm lookin' at buying this 1988 Pontiac Firebird Formula 350. It has a 4 barrel Holley carb swap as well as a shift kit in the transmission, along with chrome valve covers and other misc. visual stuff under the hood.

One of the main problems with it is that the speedometer is off. Way off. In fact, it's around 20 mph too fast. I'm thinking whoever installed the shift kit might have broken some teeth on the speedo gear. I was wondering if any of you have had a similar problem with the speedo being off, or know of anything else that may be wrong with it.

Edited June 20, 2007 by Big E

[Tirefryr 1,742]

It could be a bad speedo gear, stretched cable, someone could've installed different ring and pinion, or a speed sensor problem. Does it have ABS? I'm guessing not. 88 Formula should've been a TPI 305 or 350, so it would've had a computer in which case it would've also had a speed sensor(s) (4L60 or 700R4). ABS car will have the tranny sensor and at each wheel where ABS is active.

[Big E 4]

It could be a bad speedo gear, stretched cable, someone could've installed different ring and pinion, or a speed sensor problem. Does it have ABS? I'm guessing not. 88 Formula should've been a TPI 305 or 350, so it would've had a computer in which case it would've also had a speed sensor(s) (4L60 or 700R4). ABS car will have the tranny sensor and at each wheel where ABS is active.

Thanks I decided against the car...turns out it's been wrecked twice and somehow it has only had 4k miles put on it since 1997, in which time it travelled from California to Texas to Michigan...thank you CarFax

[ford302redneck 15]

Mines about 20 off at 60mph.

But I got different rear end Gears. If you cant get it fixed, it actually sorta helps you from speeding.

Cause you think your going faster than you are.

[Tirefryr 1,742]

Mines about 20 off at 60mph.

But I got different rear end Gears. If you cant get it fixed, it actually sorta helps you from speeding.

Cause you think your going faster than you are.

And it also spins your odometer faster than it should be causing increased superficial mileage which is bad for resale.