i have a 1997 ford f150 super cab with a 4.6 engine i just swoped out the

[gwen]

engine it is idelind but at 550 rpm? and flexes up and down a little bit when i put it in gear it dont change this is an automatic when in drive i give it gas and it wonts to cut out if i hold the gas feed down to about 800 rpm it dont seem to act up can some one offer me some advice thank you i also put in the same engine and i used the intake ald every thing else off the old engine