If it's not the fuel, Keith Lukowski, owner of Stan's Automotive on the south side, wonders why he spotted higher than permissible alcohol in a Ford Taurus he recently serviced.

The car has a button that, when pushed, displays the alcohol content in the gas tank. The car has consistently showed 10%, the maximum allowed, until about three weeks ago when it jumped to 20%.

"I was real shocked to see that it went that high," Lukowski said.

Too much alcohol can cause injectors to stick and, over time, can degrade electrical function, he said.

Jim Linder, an expert on fuel injectors of all brands, says multiple problems - including poorly designed injectors, increased environmental regulations and reformulated fuels - are to blame.

"Every manufacturer, if you take them all, they all have a little different disease in the family," said Linder, whose company, Indianapolis-based Linder Technical Services, reconditions more than 50,000 injectors a year.

Some leak, some corrode, some can handle reformulated fuels better than others. He ranked Nissan and General Motors among the worst. Ford, which primarily uses Bosch injectors, sees the fewest problems, he said.