thats exactly what happened to me, everytime making a left turn after driving on the highway, or driving at one consistant speed for more than a few min. You'd think the dealer would be able to pull that safety type of problem up on the computer, but they didnt find anything. I've asked a few ford mechanics who said normally these engines have bad iac valves and also vacuum leaks..... i'm goin to try harder in finding a vacuum leak. i definitely hear a loud hissing noise from the iac and also a lot of noise gets transmitted through that plastic intake. so its hard to tell, just keep sprayin the carb spray around the joints again...