My 71 Tbird with 43K miles stalls when driving. The car starts and idles fine. Get on the freeway and around seventy to seventy five it starts to stall. I and nurse it back home by feathering the gas pedal.

EVERYTHING has been replaced:
All electrical including changing points to Electronic Ignition / Fuel Pump / Vacuum Lines / Professionally Rebuilt Carburetor / just to name a few items.
Checked the fuel pump, its working.
Checked for any leaks around the carb or vacuum leaks.
Checked timing and all wiring including plugs firing.

For the first five miles or so or unless I get on the freeway the car will run fine. Again I can feather the gas peddle to keep it running and then drive easy back home.

Anyone have any where else to look?
Thanks.

It sounds like the fuel filter is getting clogged. You may have rust in the gas tank and that is clogging the filter at higher engine speds. I don't know what type of fuel filter you have on your engine, but if is like a 390, it is next to the fuel pump, and looks similar to an oil filter. If that is what you have, unscrew the case and pour the gas into a glass jar and wait a day or two and see what settles to the bottom of the jar. If you see a lot of redish/brown stuff that is probably the problem. If you don't have that type of filter, try installing a clear inline filter and see if that fills with junk.

Jim, Thanks for the reply. I checked the fuel filter that is located next to the carburetor and its clean. I can see right through it. And the filter only has less than a hundred miles on it.

It could be the pick-up in the gas tank is getting clogged with junk and then when you shut down the stuff falls back into the tank. I'm not sure but I think there is some kind of screen on the fuel pick-up.

Interesting this begins to happen at higher rpm. Have you checked to see if the vacuum advance is working? Also consider getting the engine temp checked with a laser based reader after a good long drive.

Good luck, Vince

Thanks for the input guys. After checking things further, I noticed exhaust coming out where the steel vacuum lines are inserted into the manifold. There is a small diamond shape plate that is bolted to the manifold where the steel lines are inserted.I see exhaust exiting when I rev the engine and there is exhaust residue next to this plate. Now I am sure there should be no exhaust coming out of that area. So is it a blown gasket? Clogged exhaust? Is this why the car wants to stall?

Another update: I disassemble the plate where the vacuum lines are connected to the manifold. When you pull the plate there is one continues U shaped tube inserted into the manifold. I am assuming it is inserted into the manifold for heat or something because it does not open into the manifold. There was a old metal gasket that was blown on the plate. I cleaned it and installed High Temp gasket sealer that takes 24 hours to setup. Now could that have effected the performance of the engine and make it want to stall?

After reading all of the posts on this topic, I still have to go with fuel starvation, even though your fuel filter is clean at the engine. There is a "sock" on the pickup tube inside the gas tank. This can get clogged with rust and crap and at low engine RPM it's usually not a problem. But start sucking hard through that sock and it won't feed the fuel it needs to. Also, there's a short rubber hose connecting to the fuel sending unit (which is the fuel feed line) where it connects to the hard fuel line to the engine. This hose could be soft by years of fuel and environmental wear, and it could be collapsing under vacuum pressure. It's easy to pull the fuel sender out when the tank's almost empty. I'm not sure if your model has a fuel drain in it, but you may be able to remove the tank easily enough and have it boiled/cleaned out at a radiator shop.

I seriously doubt that an exhaust blockage would be the culprit unless it was a very, very bad blockage, and even then it would show at low RPMs.

Ace, Thanks for the reply. For what its worth I disconnected the fuel line at the carburetor and pumped a half gallon of fuel into a glass jar and let it set overnight. The fuel was crystal clear in the morning. Of course this was a cold start at a idle that drained the carburetor bowl only, so maybe not a good test for a contaminated fuel tank.

I did replace the rubber fuel hose that goes from the steel line to the fuel filter mounted on the carburetor. Only a two inches in length.

To locate the rubber hose that comes of the fuel sending unit is accessible without dropping the fuel tank?

Before I drop the fuel tank I was looking for any other possible problems. Thanks for the suggestions.

Another Update: I now find out that when I step on the brake the power antenna does not work. The lights have been flickering slightly at a idle. The car also seems to want to stall when I apply the brakes. Maybe nothing to do with the carb or fuel supply. Maybe a bad ground? Anyone now where to start looking for a bad ground on a 71 Tbird?

Okay, that update IS news. Look at either your alternator or V-belt. Makes sense that it's not giving up enough power/charge at full(er) throttle. Add to that your powered accessories' electrical confusion and I'll bet it's either your alternator or battery.

Your '71 may have a different fuel tank configuration than my '67. Mine's mounted vertically in front of the trunk. Yours may be lying flat under the trunk. So yeah, you may have to drop the tank to get to the sending unit and draw tube hose. HTH.

Another Update: I replaced the Voltage Regulator and the Power Antenna and Brake Lights now work OK. Not sure that was the problem because it did not clear up right away. The car still stalls.
I am going to have the Alternator checked. It only stalls when driving after a few miles or on the freeway and if I jump on the accelerator. Could the Alternator not be producing enough current? The car starts at the turn of the key every time and the lights are always bright. I do see the lights brighten when I accelerate.
It is something to do with the engine when it gets hot.
For now I am ruling out fuel because everything checks out.

Is There any Motor Heads that know the 429 ThunderJet?