I have a 1985 dodge diplomat with 44k miles. It had the computer controlled holley carburetor. The car just would sometimes run, sometimes not. It had been screwed with though the years by the previous owners. So what I did was:
Remove all emissions, computer.
I bought a carter bbd2 carb and rebuilt it myself.
Installed a new vacuum advance distributor.
Also did a hei module (made by msd) with a ford tfi coil (used)
New plugs,cap,rotor, fuel filter
Timing is sat at 9 before. I have tried adjusting a degree at a time and this is the best.
I also upgraded the grounds and power cables.
The car runs great going down the road, BUT it has a rough idle, And when you first start the car (cold) You can hear a slight tap. When warm the noise goes away. Also when cold it is really rough idle. But warm the idle improves but is still rough.
Ideas as to what I'm messing
Thanks

 

The choke could be set too rich also adjust the mixture screws for highest idle

 

I have tried it without the choke and no change

 

The tapping always has me verify oil pressure cold and hot, idle and above. Anytime I have a rough running engine after exhausting the obvious a compression test is in order, both cold and hot in this case.

Have you run it with a vacum gauge, cold, hot, idle and above? This step could give you an answer easily.

 

I will hook up a vacuum gauge and do A compression check after I get some tools.
I'll let you all know

 

Found the problem!!!!!!!!!!!!!!!

It was a clogged idle tube. It idles great, at least warm. I will found out how it idles cold in the am.

thanks guys

 

Make sure you use some type of ethanol stabilizer in your gas. If you don't start your car often enough the ethanol will clog stuff up.

 

Thanks for that I will be using this car as a daily driver.
Just need a little more fine tuning and this problem will be fixed. Then on to the next one, trust me there are alot problems needing help

 

At idle the alternator will be putting out 12.9 volts. Also the air gets warm. I have the idle set at 800 rpm. If I take the idle to 1500 rpm the problem goes away, but that way to high for the idle.
I am running the stock v belt that came with the car. The only change made was to a 90 amp alternator. I made this change before I dumped the feedback computer crap. Can I run a bigger crank pulley? Or is there something else that I should try?
Also this has the double v belt setup for the alternator and ac.

 

12.9 volts is low should be 14.2 volts Check the brushes in the alternator the wires sometimes break or get loose and dont make good contact. Bill

 

the alternator is fine. It's been checked. It all worked fine until I switched to run with out the leanburn stuff