Tesla Motors claims it has successfully ramped up production of its pivotal Model 3 sedan during the summer, fulfilling CEO Elon Musk's pledge to work out the manufacturing problems that had raised questions about the electric car maker's future prospects.

But there are questions over how successful the company really is after a group of internet sleuths found various lots and garages in California, New Jersey, Arizona and Utah where Tesla cars have been found parked up in large numbers.

Tesla had been regularly missing its production goals while amassing huge losses, fueling doubts about its ability to expand from its niche of making luxury sports cars powered by electricity to become a major automaker.

Aerial photos have been released that show hundreds of Tesla's parked up in several locations

Several locations around the country contain parking lots full of the Tesla cars. A lot in Lathrop, California is pictured here

One customer demanded to know where her new Tesla was. The frustration only grew after she saw hundreds of them parked up in a lot in Salt, Lake City, Utah

Elon Musk tweeted that there were problems with delivering cars to customers following this angry Tweet from a customer

The company announced Tuesday that it produced 80,142 vehicles in the third quarter, marking a 50 percent increase over the previous quarter and when the company hit its target for the first time in the last week of June, some questioned whether the feat was sustainable.

But it appears that there are other problems facing the company. Since July, Tesla has been parking anywhere from a couple of dozen to a few hundred cars at a lot in Burbank, California.

It's a similar story in the town of Lathrop near San Francisco where Tesla has 400 cars at an industrial site according to the New York Times.

Hundreds more have been located in in Antioch, northeast of San Fran.

Last week, the newspaper reported that another batch of 100 Model 3s cars in Bellevue, Washington with further batches in Chicago, Dallas, Las Vegas and Salt Lake City.

The company has refused to comment on the reason for the surplus other than to say there were delivery problems at one stage

Some have suggested the full lots are because demand for Teslas isn't a great as the company advertises

Internet sleuths have taken to sending up drones and even flown in private planes to snap pictures of the parking lots containing dozens of the parked-up Teslas

The vehicles, which have all been parked on private property, have been uncovered by amateur detectives many of whom have flown drones over the parking lots to take pictures of the sitting cars.

Another ended up taking to the skies in a private plane to snap hi-res photos from the air before posting them on Twitter.

The sleuths are betting that Tesla's share price will fall and suggest Elon Musk has not been truthful about the company's current situation, particularly its sales numbers.

The existence of such massive lots full of cars are likely proof that something is amiss at the company.

A Tesla spokesman, Dave Arnold, said by email to the Times that the large lots of vehicles were 'logistics transit hubs' and added, 'Anyone observing those lots will see a change from one day to the next.'

One photographer took to the skies in order to capture the cast numbers of cars sitting idle

Tesla Inc. vehicles sit in a parking lot outside of a newly constructed production tent at the company's manufacturing facility in Fremont, California

Tesla delivered 83,500 vehicles in the third quarter, which is more than 80 percent of the vehicles that it delivered all of last year - but then why are so many of the cars going nowhere?

Production increases are something Musk worked nearly to exhaustion to achieve.

He has publicly said he has been working as much as 120 hours per week and sometimes even slept on Tesla's factory floor in Fremont, California, to oversee the efforts to make more cars. The company even built a heavy-duty tent to add space to make more Model 3s.

But doubts remain whether the company can continue to crank out enough vehicles to achieve profitability, something that still eludes Tesla.

Although it successfully reached its production goals for the third quarter, getting those vehicles into the hands of consumers has proven to be a headache.

Tesla delivered 83,500 vehicles in the third quarter, which is more than 80 percent of the vehicles that it delivered all of last year.

But one other theory is that the presence of parking lots with hundreds of Teslas all parked up with no place to go, could mean that there is a delivery problem.

At one point, Elon Musk suggested that there was a shortage with hauliers transporting cars

CEO Elon Musk has pledged to work out the manufacturing problems that have raised questions about the electric car maker's future prospects

Customers have been complaining that their Tesla delivery dates have been delayed over and over while vehicles sit unmoved in lots.

One tweeted to Musk last month: 'There are 42 Tesla's sitting at the Union Pacific Railroad in SLC. My car is one of these. I've been told I was getting delivery the 8th, then the 15th, then the 20th, then the 22nd, and now my delivery has been delayed indefinite. @Tesla @elonmusk... Please make this right.'

Musk tweeted back and acknowledged the problem: 'Sorry, we've gone from production hell to delivery logistics hell, but this problem is far more tractable. We're making rapid progress. Should be solved shortly.'

Musk attributed the problem to a shortage of trucks to haul cars around the country but others disagree saying there is 'plenty of car haulage capacity.'

'The Auto Haulers Association of America is not aware of any shortage of car haulers, nor of any other automakers that are having trouble shipping new vehicles,' said Guy Young from the organization.

Musk has even said that Tesla has developed its own trailers to transport cars to customers but no new designs have been approved by the Federal Motor Carrier Safety Administration, which regulates such transporters.

The company has said that more than 400,000 customers are waiting to buy Model 3 sedans, and that each paid a $1,000 deposit. Thousands are sitting in lots around the country

Musk had promised the Model 3 would be available for as little as $35,000 but the cheapest now starts at $49,000, and is closer to $60,000 if a customer wants the Autopilot feature

Either way, it is clear that Tesla appears to have failed to set up an efficient way of delivering the hundreds of cars a day it is producing.

The only other alternative is that demand is far less than Tesla is suggesting and the reason there are so many lots full of the costly cars is because there are simply no buyers.

Musk had promised the Model 3 would be available for as little as $35,000 but the cheapest now starts at $49,000, and is closer to $60,000 if a customer wants the Autopilot driver-assistance feature.

More could be revealed in the coming days when Tesla reports production and delivery data for the last three months.

But patience is wearing thin for people who have already put down $1,000 to get on a waiting list for the Model 3.

Tesla has never turned an annual profit during its eight-year history and rarely done it on a quarterly basis, but it needs to reverse that trend to erase doubts about its survival.

The company has been under mounting pressure to stop burning through cash with $1.3 billion of its more than $10 billion in debt due to be repaid during the next six months.

Musk will give up his post as Tesla's chairman for at least three years after tweeting in August tweet that he would take the company private and had 'funding secured' for the deal.

The Securities and Exchange Commission filed a lawsuit Thursday that said the tweet constituted securities fraud because Musk knew he hadn't lined up the money for such a deal.

Critics, including some investors, had pushed for similar changes recently, arguing that a new chairman and a board less tied to Musk would be good for Tesla and its investors. Some have argued Musk should even give up the CEO role and assume a post such as chief technical officer.

The SEC said it wanted to bar Musk from serving as an officer or director of a publicly traded company, a scary option for investors who felt Musk was nearly synonymous with Tesla and that another executive would have trouble managing Tesla's manufacturing challenges and keeping the public satisfied in spite of Tesla's substantial debts.