[79TA455]

Ok, so I posted about 5 years ago when I first took this car the strip about it bogging and life took over and I never had a chance to look further into the issue and it never bogged after that.

Fast forward to now, and the car is bogging way more. I checked the secondary air valve and the tension was quite low as I could push open the flaps easily and they would not snap back shut. I tested by putting some more tension on them by loosening the allen head screw and turning the screw just enough so they snap back. Test drive and no change.

The bogging was first noticed going from 2nd to 3rd but it does not matter, as long as it is WOT. It has occasionally done it at part throttle too but that is intermittent.

I warmed the car up and took it for a drive and then removed the shaker and air cleaner assembly. I then checked the flaps on the secondary's and they were closed (by vacuum). I pulled the throttle cable wide open and the flaps on the secondary's only opened a few cm's and I never got that "quad bog" sound. I also never notice that sound when driving WOT.

I checked the choke vacuum diaphragm on the front passenger side of the carb and it appears to be ok (as far as I can tell) but when it is running, the vacuum from that seems pretty strong and maybe that is stopping the secondary's from opening all the way?!

It seems to me to be a fuel delivery issue and I thought about the fuel filter but I changed that less than 500 miles ago. I checked the plugs for cracked ceramic and wearing on the firing end. I also double checked the gap (.045 on AC Delco R45TS).

Stock 1976 Trans Am 400 with Quadrajet.