Kickdown issue

[My3buicks]

I put a little over 500 miles on the Centurion this weekend. It ran beautifully except for an issue I had when I went to pass a car on a country road.

First I have a little hesitation off the line and I have assumed it needs an Accelerator pump but it's not to bad so I just havn't done it yet.

When I kicked it down into passing to go around this car, it took off like a bat out of hell and I no sooner got out beside the other car and it just bogged down and then took off again and then bogged again like it was starved for fuel. I tried it several other times with the same results.

There are no other issues driving, it's pulls hills fine, accelerates onto freeways fine. The secondaries are opening nicely. Getting respectable gas mileage (17mpg) It's just when I really romp on it and kick him into passing that it does this.

Any thoughts from the more mechanically minded.

My thoughts are fuel filter, accelerator pump or vacuum leak.

[Smartin]

Check the points/dwell.

Then check the timing

[My3buicks]

I should add it has what I believe is a petronix or similar installed

[Smartin]

hmmmmmmmmmmmmmmmmmmmmmmmmmm

Check to make sure your distributor shaft play isn't too much. side to side...that will effect the pickup of the module big time.

It could be several things at this point.

Check to see if your secondary and choke pulloffs on the carb hold vacuum. (these are the small plastic vacuum diaphragms on the passenger side of the carb)

Double and triple check all vacuum connections.

[Robroy]

It’s a long shot but you could check the gas tank ventilation, if it for some reason got blocked the fuel pump has a hard time pumping the fuel from the tank due to the under pressure created in the tank

[Robroy]

It’s a long shot but you could check the gas tank ventilation, if it for some reason got blocked the fuel pump has a hard time pumping the fuel from the tank due to the under pressure created in the tank

[centurion 455 ragtop]

Keith you said on an earlier post your car has not been out for a dew months. I would say fuel or ignition. Check all the simple things first like what Adam said. Inspect under the dist cap and check the timing and vac lines for a brittle cracked hose. Next, change the fuel filter and pick up a can of gumout and clean out the carb while she's running. A fresh tank of high octane fuel will help too. Fuel could have gummed up inside of the carb. More than likely the problem will be one of them.

I used ti have a pr

[centurion 455 ragtop]

Keith you said on an earlier post your car has not been out for a few months. I would say fuel or ignition. Check all the simple things first like what Adam said. Inspect under the dist cap and check the timing and vac lines for a brittle cracked hose. Next, change the fuel filter and pick up a can of gumout and clean out the carb while she's running. A fresh tank of high octane fuel will help too. Fuel could have gummed up inside of the carb. More than likely the problem will be one of them.

[My3buicks]

Thanks guys. I had cleaned the carb right before I left. Also put a can of Seafoam to run through the first tank. I topped off before I left with Sunoco Ultra and them refilled outside of Columbus on the way back with Ultra
Will look at a few of the suggested things and see what happens.

[My3buicks]

Thanks guys. I had cleaned the carb right before I left. Also put a can of Seafoam to run through the first tank. I topped off before I left with Sunoco Ultra and them refilled outside of Columbus on the way back with Ultra
Will look at a few of the suggested things and see what happens.

[Trey]

i had the same problem with my trans am's 455. turned out to be a weak fuel pump. it supplied enough volume to run around normally, but under hard acceleration she would fall flat on her face. new pump solved the issue.