I just picked up my first 85 bronco with a 351W automatic. I have been having trouble getting the thing to idle in drive or reverse. It seems to run fine in Park or N but when I shift it in to Reverse or Drive, the idle drops and it begins to run rough and then it will usually die unless I give it full throttle. Once I get off the line it runs great but when idling at a stop light or crawling along at idle speeds the thing starts to miss then dies. I can smell unburnt gas and my plugs were black when I replaced them.

Heres what I have tried so far:

*Check timing and set to 10 deg
*Replace spark plugs with Motorcraft @ .055 gap
*Replace Ign Coil w/ MSD blaster
*Adjusted Idle speed (I set this higher than normal to help compensate for rough idle)
*Adjusted idle screws on carb
*Cleaned carb with carb cleaner
*Coated spark plug wire connections with Dialectic grease
*new PCV valve
*new fuel filter

I have my smog pump removed and all the vac lines capped off. I also want to remove my EGR system as this is going to be an offroad only truck.

Could it be malfunctioning carb, vac leak, fuel pump, or Ignition Box?

I noticed that my Carter AFB carb is constantly dripping fuel from right below my butterfly choke on the front 2 barrels. The back 2 barrels never seem to do anything even when i blip the throttle. No gas comes out or anything. Is this normal for a carb to act?

Thanks, Im new to the world of carbuerators and I find them more complicated than my FI VW's!

 

sounds like you need a new carb or at least a rebuild. when you set the timing did you plug the vacum advance?

 

yep plugged it at the carb and at the distributor.

 

today I swapped out carbs with a known good one and the problems seem to have been fixed. Good news too, I didnt want to sink any more money in to this