Problems had plagued the police version of the Ford's Explorer SUV for months with officers getting sick and lawsuits being filed.
The car maker has said that regular Explorer drivers "have no reason to be concerned," but complaints from first responders continue piling up.
The vehicles are not street-ready when they leave Ford's factory. It's up to each police department to personalize them and add law enforcement equipment.
Ford is still investigating what's happening to their vehicles to cause the concerns but has said that those upgrades may be the issue.
How are police departments modifying their cars?
Before officers actually drive them, these vehicles go through a full police "makeover."
Most of the tech that officers use like radios, dash cameras, computers and speed detectors are installed after Ford makes a delivery.
It's the same case for emergency lights and decals.
"It comes equipped from the dealer as a basic car," Elgin, Texas, Police Chief Chris Bratton told CNN affiliate KXAN
But what has gone wrong?
All or some of that equipment comes with a lot of wires, meaning that technicians have to drill access holes into the rear of the vehicles.
"We've discovered unsealed spaces in the back of their vehicles related to the installation of their police equipment," said Hau Thai-Tang, Ford's executive vice president
for product development and purchasing.
Thai-Tang explained that if holes are not properly sealed they can "allow exhaust gasses to enter the vehicle's cabin."
Police cars are often left running between calls, while officers fill out police reports and during traffic stops.
Who is making the modifications?
Every department goes through their own process. Some commission the work to specialized companies and others do part of the work themselves.
In Austin, the city's fleet services manages the vehicles but the SUVs are actually fitted by three different places, a city spokesperson told KXAN
A Ford dealership in Silsbee, Texas, works on some of the changes, like transforming the backseat into a prisoner transport area and changing the locks.
The city's fleet services gives them the police unit touch with bumpers and decals before another department adds equipment such as radios, sirens and dash cams.
What's next for the affected SUVs?
Ford has sent technicians around the country to inspect the vehicles while it continues investigating.
Last week, the company offered to cover specific repairs for the Explorer's with leaks.
"Ford has really taken this by the horns," said Galveston Police Captain Joshua Schirard.
His department decided to pull all their Ford Explorer SUVs on Wednesday when an officer reported he felt light headed following an overnight shift.