US STOCKS-Futures up, indexes on track for 4th week of gains
* Trading expected to be light ahead of holiday
* Indexes on track for fourth straight week of gains
* Chicago PMI, consumer sentiment data on tap
* Futures up: Dow 42 pts, S&P 5.75 pts, Nasdaq 12 pts
By Ryan Vlastelica
NEW YORK, Aug 29 (Reuters) - U.S. stock index futures were modestly higher on Friday, suggesting the market's recent upswing was intact and pointing to a fourth straight week of gains for major indexes.
* Stocks have been strong of late, with investors taking any opportunity to buy on dips. However, this week's trading volume has been among the lightest of the year, and that is likely to be more pronounced on Friday, ahead of the Labor Day holiday in the United States for which markets will be closed on Monday.
* Investors are looking ahead to more economic data, which has largely been strong this week. July personal income and spending data will be released at 8:30 a.m. (1230 GMT); both are seen up slightly.
* After the market opens, the MNI Chicago Purchasing Manager's Index and the Thomson Reuters/University of Michigan Surveys of Consumers will be released. Both are seen rising modestly. Continuación...