Houston is weathering a prolonged plunge in oil prices, but the city may have an even bigger problem: its pensions, the Wall Street Journal reported today. Though economic growth has only slowed, not stalled, in Texas’ largest city, its finances are showing what several investors and analysts describe as warning signs. Those include a rapidly growing gap in funding its retirement plans for public workers and a limit on its revenue-raising capabilities imposed by a voter-approved cap on property taxes. The $3.2 billion pension-funding gap is threatening Houston’s Aa2 credit rating from Moody’s Investors Service, hurting demand for its debt and emerging as an issue in the city’s mayoral race. Moody’s this summer warned it may downgrade the city’s debt if Houston fails to address its pensions, noting the cap limits the city’s financial flexibility.