Working on a '92 aerostar with a 4.0, a4ld and 240k miles. it runs perfect 95% of the time, but it has an intermittant problem i just cant figure out!! i've tried just about everything. swapped the MAF, installed a new fuel pump, new fuel filter, new plugs and wires.. tons of new stuff.. anyway, it has these symptoms: first, at idle, it will suddenly go into a rough idle, and has no power (press the accelerator and nothing happens) the truck will barely move... it also does this while cruising down the road too.. i'll be cruising along at say 30mph, and suddenly it'll loose power and i wont be able to keep going.. but if i shut off the key and restart it, it's perfect again. the other thing i've noticed, and i'm not sure if it's related or not, is at half throttle or more it pings badly. any help would be greatly appreciated.