Bogalu

Got a 69 with a 351w with a 4bbl holley 670 double pump. It pretty much has trouble altogether with accelerating. If you pedal to the metal then the car will die. So You got to ease into it until you get the rpms a little higher. Then you gun it but it sounds like the car is spitting crap and it looses power then gains it then looses it then gains it, all in a very fast sequence. The carb is new, same with fuel pump, filter, lines, ect. Anything fuel dilivery wise is new. Same with spark plugs so I know thats not the prob. The car was running great when I got it then it slowly got worse until It got the point where its at now... when I cant even feel confident against a honda in the streets. And when you lay off the gas when your at high rpms it sounds like its spitting crap. Hard to explain but thats how it is. Help me out guys. Thanks a lot.

67mustang302

Gonna have to be more specific. But if it's gotten worse, then plugs/wires/cap/rotor could have gone bad, or something clogged in the carburetor etc. What exactly does it do?

69thunder

Check timing and ignition system. Carb could be out of adjustment. New does not mean tunned correctly.

Daze

the stutter at acceleration sounds like the accelerator pump is not working correctly. With the car off look down the carb and work the linkage. See if a stream of extra gas shoots in to bore. If it does but is small adjust the linkage to get a bigger squirt. The other symptoms sound like one of two things either your vacuum advance is not working correctly or you have a vacuum leak. I am thinking it is a vacuum leak, but I would start with the vacuum advance and put a timing light on the car and then increase the vacuum. If the advance changes you know it is not that. Also make sure the port you have it hooked to on the carb is pulling vacuum. If it is not in the advance then start looking for leaks around the base of the carb, unplugged holes/ports on the carb and check the hoses for cracks.

Sean W.

it sounds to me like its a timing problem...

but, check the fule lines, fuel filter... check the spark of the plugs, dont check just to see if they spark, but check to see the intensity of the sparks... if its weak, check the dizzy, the coil, all electical connections...

start with that.. and let us know how it goes..

STANGANDGOAT

I hadasimilarproblem a long time ago, it was a vacuum leak.

Gun Jam

I second the fuel pump...with vaccum leak a close second

-Gun

jlg2002

You're describing a fuel delivery problem in good detail. It pops & bogs down on initial throttle opening and then slowy catches up. The question is when it catches up, is it running strong or just running? if running strong, look at your float level and accel pump if it just runs, Look at fuel pump volume & pressure, fuel filter for clogging, accel pump operation and adjustment. (New parts go bad BTW)

Clu7ch

I agree. In my experiance with vacuum leaks (a.k.a. me not replacing the hose I moved out of the way while working on the car) if you floor it it stays on, but it will not idle for long.

My LeSabre had a FP problem and the pump died. When I would floor it it would stall. It was getting too much air and cutting out. Check your lines, and filter and if not those, than your pump may be bad.

Easy way to test: Get starting fluid. Disconnect the fuel line and put into a small clean bottle. Spray quick start into the carb and have someone start the car while you continue spraying. Watch the fuel line and see if there is flow and at the same time listen to the motor and play with the accelerator to see if there is any variance as you open the throttle similar to what you experianced while driving.

- Clutch

Bogalu

Wow I had about 10 different opinions here. But I will let you know that the carb, pump, lines, filter is only a couple of months old. If it helps. I thought a vacum leak myself. But not sure. keep giving your opinions guys. Thanks. ttyl