Please advise... stuck at work

[Franks68coupe]

I've been working my *** of trying to get this thing to at least run semi-correctly. Over the weekend, re-set the timing, fixed an exhaust leak, and re-did the vacuum line to the tranny. Took it out yesterday for a spirited drive (just a few miles), and all seemed good...

Cut to today Feel good about it, and take it to work. Halfway here (whole trip is about 6 miles one way), it starts stumbling at lights, and dies a few times, fires right back up. I do my work and go out to where it's parked, fires right up, let it get up to temp, and when I put it in gear it dies. Everytime. I was able to squeeze under and feel the vacuum line to the tranny is right where I left it... dizzy hasn't moved timing set to 12. I brought a backpack full of basic tools... vacuum is reading at around 19. If it starts to stumble I can jam it into neutral and it idles fine. This is on a 351W, with FMX. Any thoughts or suggestions? I can probably limp it home doing the neutral thing... but I don't want to run it if I'm hurting something.

I'm just about at my whits end with this thing

[Bucket Lister]

Put a timing light on it when its running poorly. If the timing has changed, your timing gears are worn. Nylon toothed gears are known for this.
Put the vacuum gauge onto a full manifold port, run the hose under the hood, duct tape it to the windshield so's you can se the dial from the driver's seat. If vacuum is inconsistant during idle (like at a traffic light), you are beginning to narrow down the problem.
Do the same thing with a fuel pressure gauge.

This may be a hit or miss system, but it works to narrow down a problem.

[Chase]

Check the idle setting on the carb? my gramps had a new carb put onto his 69 New Yorker, and the PVC line had come lose, and when they set the carb they got it running great, we saw the line loose, hooked it up and the car wouldn't run for beans. Had to re adjust the the idle setting to raise it up some. I couldn't drive it to save my life, it would die even in Neutral, had to keep my foot on the gas, barely limped it back to the shop where he had the work done on it, so I would say sounds like something with the idle setting on your carb, check them out and see what that does for you. sometimes its the little things we often overlook that gets us in the end.

[Franks68coupe]

I'll double check the idle setting... I dialed in the carb again after setting the timing over the weekend, but I can crank it up to get her home.

Timing gears sounds like something I should look at. The timing has been unreasonably hard to nail down.

Just really sucks that it trcked me into feeling good and then relaly sticking it to me at work in the parking garage. I swear it has a personal vendetta against me for something.

[22GT]

Sounds to me like something is dying in the ignition.

[zanado]

I had a simalar problem on my 69 351 and fmx hard starting cold and not real smooth new carb so I figure setting on carb or vacum leaks no luck so for 39.95 replaced the dizzy and holy crap could not believe the difference both had new points etc start up smooth drive great Im not the brightest but just a thought

[Blues Power]

im betting is a bad coil or foulded plugs or wire related.

since you say the vac is steady at 19 that imo would eliminate the carb and timing issues.

[67mousetang]

Originally Posted by 22GT

Sounds to me like something is dying in the ignition.

+1

are you running points and condenser? any moisture or crack in the cap?

[Joe]

Originally Posted by 22GT

Sounds to me like something is dying in the ignition.

+2 Sounds a lot like what my '72 was doing when the points died.

[JonK]

Have you changed the fuel filter lately or installed a clear plastic one between the FP and carb? Sometimes clogged fuel line/filter will work fine at idle and stop up on increased load.
Have you looked at the harmonic balancer to make sure it's not slipping? they have a rubber sleeve between the two parts that dries out/cracks eventually.
Jon

[Jeff73Mach1]

How old is the vacuum modulator at the transmission? When they fail they will allow the engine to suck up transmission fluid and will shift really hard and late most of the time. Cheap and easy if this is the problem.

[Franks68coupe]

Recently instaled a pertronix distributer, new coil, and second strike box. Also put in new plugs, and wires when I did it. I just had a lightbulb go off... If I forgot to bypass my resistance wire... This would happen? Gonna crawl back under the dash and double check that.

[Franks68coupe]

Just took out my multi-meter and reading 14V to the coil. It couldn't idle amy smoother... Just dies when I put it in gear.

[22GT]

That's a weak spark. Fuel problem would take longer to lose power.

[SchnorrCS]

I'm thinking vac modulator on the trans.....