84 GW spitting and sputtering

[Clonerjeeps]

I have a 1984 Grand Wagoneer with a 360. When the transmission is in neutral, the motor will rev up with no problems, no spitting or sputtering. When the car is driven on the highway it will reach 60 to 65 with little problem. But, when you go to accelerate to pass another vehicle the motor will spit and sputter and will refuse to increase its speed.

I have replaced all plugs, plug wires, distributor cap and button. I have also replaced the coil and fuel filter and still have not changed the spitting and sputtering.

Any ideas or suggestion would greatly welcome.

[Ryan]

it could be a lot of things:

vacuum advance
timing
carb settings
partially clogged muffler or cat

does it also do it from a dead stop when accelerating? Or only when at speed then trying to pass another vehicle?

[Clonerjeeps]

Hey Ryan,

This is Charles that bought the maroon seat. The jeep is mainly doing it when I am driving down the road at any speed over 35mph.

Thanks

[Ryan]

Hey sir, good to hear from you. With it being over 35, each of the above is still a valid place to start looking. I'd start with timing first. If you are still running the motorcraft stock dizzy, then disconnect the vacuum advance hose from the dizzy and plug the hose and set it out of the way; adjust timing at idle to 12 degrees BTDC (make sure idle speed is also set properly before doing this). Then, reconnect the vac advance hose and take it for a drive. If it still does it, get some Berryman's carb cleaner and with the engine running and air cleaner cover removed, spray a little at a time inside the carb and all around the inside of the carb bowl. Take it for a drive again and see how it's acting.

Also, is your fuel filter the single-in and double-out style? If so, is the smaller return nipple oriented above the carb-outlet nipple? If not, make sure to correct that as it makes a difference while driving.

If those don't fix it, you should also start looking at your plugs and plug wires to make sure you don't have a dead cylinder or arcing on the wires. Sorry for all the tail-chasing, but with stumbles and misses, there are a ton of possible things it could be.