UBS has maintained its positive stance on FTSE 100 engineer IMI but warned that investment case is under pressure.The broker says that IMI's second half "disappointed" as revenue growth slowed to 4%, from 8% in the first six months.Nevertheless, the firm kept its expectations for the full year. "It seems the self-help story is in full flourish though as margins have continued to surprise and the improved profitability is able to offset the weaker top-line," UBS said.The broker cuts its 2012 estimates by 4% ("reflecting more cautious growth rates") and reduces the target price from 1,000p to 950p.However, a buy recommendation is kept: "With 2011 not looking like the record year of growth we expected, our latter point is under pressure but we stick with our buy given IMI's not priced for much anyway."Shares were 0.57% lower at 790p by 10:08.BC