Hi guys, I've been fighting a problem off and on since I got my '69 Mach 1 back together. I've had lots of '65-66s, and to me, the gas pedal on the '69 has never felt right. It's always felt like the cable is binding slightly, and recently, the throttle started hanging slightly open above idle. It was annoying but not especially alarming, as you could kick the pedal slightly and it would back the accelerator linkage back down to idle.
Since this is the first '69 I've had, I've not had much experience with the cable-driven throttle setup. I'm using a new reproduction throttle cable from NPD. So far, I've:
1. Taken the cable back out and oiled it until oil ran out of both ends
2. Verified that the cable is seating properly both at the gas pedal and in the bracket on the back of the carburetor
3. Tried a concours AMK reproduction throttle return spring, as well as a variety of other generic parts store springs
I'm running a newer Edelbrock 1403 (500cfm) 4-barrel carburetor along with the original throttle cable bracket. The only modifications I've done are as follows: When it became apparent that the throttle cable linkage wasn't going to be travelling straight, I made a bracket that moved the factory throttle cable/return spring bracket towards the driver's side of the car in order to give the linkage a perfectly straight path of travel.
As far as I can tell, this setup should work, and should work well. The cable runs perfectly parallel to the carburetor linkage, and it doesn't appear to be binding at all. However, the pedal is still stiff throughout its entire motion of travel, and it feels like there's way more resistance than there should be, along with the aforementioned problem of the pedal hanging slightly above idle. When I install a stiffer return spring, it eliminates the problem of sticking above idle but makes you want to drive with two feet on the pedal!!
I know this is something that would be much easier to troubleshoot in person, but I was wondering if someone else might have any ideas or had run into a similar situation before. I absolutely don't know where to go from here, and the car is staying parked lately because I can't stand driving it.