I have a 1986 F-150 with a 302 EFI. The engine appears to have a erratic idle when cold. The engine will bounce around from 450-700rpm and sometimes even sounds like it is about to die. The engine also starts surging whenever the kickdown is engaged at speeds upwards of 50 mph. I have new plugs, plug wires, distributor cap, and rotor button. This is my first Ford vechile to own and I'm not very knowledgable of them. Any information on how to correct these two problems will be greatly appreciated.
Thank you for your assistance,
Joel

 

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Joel, try taking a can of carb. cleaner and mist it around your intake runners if the motor surges then try replacing your intake gaskets. I am not sure but the iac could also be at fault, which sometimes you can clean them out with that carb cleaner, but the condition you are describing to me sounds like a leak on your intake. hope this helps you own the best made truck now enjoy.
bill

 

also have a fire extinquisher on hand just in case your arcing somewhere because carb cleaner is very flammable.
good luck
bill