It hasn't been a good month for owners of Ford F-150s or those considering purchasing the classic truck, as millions of vehicles have been recalled for two separate safety issues.

In April, the National Highway Traffic Safety Administration forced the automaker to recall F-150s made between 2003 and 2006 due to a problem with airbag wiring that could cause the safety devices to unexpectedly deploy. Now, F-150s made between 1997 and 2001 are being investigated by the NHTSA after the bureau received complaints of corrosion possibly causing the fuel tank to fall off.

The 2.7 million vehicles that are potentially affected by the issue aren't yet subjected to a recall, but one seems likely considering the NHTSA's recent modus operandi. Ever since the Toyota scandal, the government body has been opening its own investigations and forcing automakers to recall more vehicles.

The airbag wiring incident is a prime example – Ford said that only 144,000 vehicles had the problem, but the NHTSA insisted on the automaker bringing back 1.4 million. Combine that with the 2.7 million trucks currently being investigated, and Ford may soon be looking at a combined total of 4 million F-150s recalled in a one-month span.

Drivers in the market for a used Ford F-150 shouldn't necessarily disqualify the vehicle, but they should check to ensure its either unaffected or has had the proper repairs.