All these new parts... & still it doesn't run right

January 1, 2020 | By Staff


My 1973 Javelin AMX Go Package 360 runs OK when started cold and has plenty of horsepower and will run down the highway at 70 mph, no problem. However, once it warms up it starts running rough, almost to the point where I can’t keep it running, but doesn’t seem to have a miss.

It is in a restoration and repair shop where they have done the following: Installed points, condenser, coil, plugs, distributor cap, gas cap, and fuel pump; plus they have rebuilt the carburetor and checked the timing. The engine temperature seems to be fine and is not overheating when running on fresh 91 octane gas. Is something “breaking down” from the heat? The engine has 101,000 miles, has never been apart, and does not burn oil.

Any ideas on where to look?


Now that all of those components have been replaced, you need to go over everything and make sure they are working together as they should.

A few things come to mind as possible problems. Number one would be to check the vacuum advance if your Javelin is so equipped, and then check the intake manifold and carb for air leaks using a vacuum gauge.

The next item I would check is the choke on the carburetor. Is it opening completely when the engine heats up to normal operating temperature?

I also would make sure sparkplugs are the correct heat range for the engine.