This is the governments fault, the truck ran fine before I messed with it to pass their stupid smog test. I have a Carter AFB 625 cfm 4bbl carb on my 400. It is a carb Carter made for Ford vehicles. I was trying to get it to pass smog, I swapped metering rods a few times, but ended up just swapping the 600cfm edelbrock carb from the capri to get it to pass. I put the carter back on, with the original metering rods, and for the last 2 days, the engine wont idle down unless I stomp the gas pedal real quick. Today, I went out and jiggled some parts, but didn't change anything, and now when I give it gas, it hesitates and then goes, and if the idle is set below 900rpm, it will continue to idle down until it dies. I have the idle set at 1000rpm, but the hesitation is killing me. The only thing I can think of that I probably should have done, was replace the carb base gasket. Does this sound like it could be a vacumn leak? and it also takes about 20-30 seconds of turning the motor over before it will start, and then there is a real bad smell of gas. IT used to start up right away. Please help, this truck used to run so good just a few days ago, and now I dread having to go anywhere. One other thing I noticed is that where the hot wire connects to the choke, is loose, and can swing over to touch the negative wire. I dont think this can happen on it's own, but do you think the electric choke could be fried too?

 

It sounds like an air leak. Get some carb cleaner and spray it around the base of the carb. Also did the smog tech adjust your timing? If so put it back ware it was ( Typicaly they will retard the timing).

 

It was the base gasket, I shoulda replaced it the first time, but you do wierd things when you are poor, and the government keeps wanting more money to fund their dirty habits. It runs like ti used to, I am so relieved. My truck certainly didn't like that other carb, I had no power, and the it made the motor diesel when I would shut it down.