Federal regulators are investigating 865,000 General Motors Co sport utility vehicles for potential faulty fuel gauges that could mistakenly tell drivers their vehicles have more gas than they do.

The National Highway Traffic Safety Administration said on its website it opened a preliminary investigation covering Chevrolet Trailblazers, GMC Envoys, Buick Rainiers and Saab 9-7s from model years 2005-2007 after receiving 668 complaints alleging inaccurate fuel gauge readings.

Of the complaints over the weekend, 58 incidents were alleged to result in a vehicle stall and 43 of those occurred because the fuel level reading indicated more fuel than what was actually in the tank, NHTSA said.

One complaint alleged the affected vehicle stalled while exiting the interstate and was struck from behind, according to NHTSA.

NHTSA said the complaints show an apparent increasing trend, with most complaints received within the past year. It added it has opened preliminary probes for Ford Motor Co and Honda Motor Co Ltd <7267.T> vehicles.

NHTSA received 18 complaints concerning the liftgate glass on the rear doors or hatches on 200,000 Ford SUVs. The reports said the liftgate glass on Ford Escapes and Mercury Mariners for model years 2010 and 2011 could spontaneously shatter when the liftgate was opened or closed.

In one incident, a consumer reported that she and her 10-year-old son were cut by glass fragments, NHTSA said. Many of the incidents occurred during cooler temperatures.

The safety agency also said it opened an investigation covering 288,000 Honda CR-V SUVs from model years 2002 to 2004 for complaints that the headlights stopped working. NHTSA said it has received 12 complaints alleging both low-beam headlights stopped working simultaneously.

Several of the complainants report the headlight switch and its wiring harness connector required replacement to repair the low beam head light circuit, NHTSA said. It was also reported the switch and connector had become damaged by overheating/melting.

Spokesmen for GM, Ford and Honda said their companies are cooperating with NHTSA.

(Reporting by Ben Klayman and Deepa Seetharaman in Detroit; Editing by Derek Caney)