Over 20 years ago I needed a forklift for my business. I purchased one and had it converted to run on propane. I think the cost to convert it was about $500 with the tank. Question, if running on natural is cleaner, cheaper and the technology has been around for over 20 years, plus all the Gas Company trucks in Southern California are all ready running on natural gas why doesn't Ford offer a natural gas upgrade kit for all their cars? They will make billions and screw Exxon-mobile (aka Standard Oil)and the Arabs at the same time.

In answer to your questions: Detroit did offer many CNG powered vehicles (typically trucks) for years. The demand was low. With the cost of natural gas these days, its still no bargin. And the range is limited as the tanks that can hold the pressure are large.
Some aftermarket conversions are done poorly and result in higher emissions.
As for screwing the Big Oil, you may want to check on who is marketing natural gas. It's often those same people.

I have also been in a gas and oil drilling partnership for over 22 years. Yes the price of natural gas has gone up but not nearly as much as oil. And neither Exxon-Mobile nor Shell nor any other major has anything to do with mine or any other partnership that I know of. Frankly when you're that big and fat who needs to sell to limiteds. As far as hours of operation per dollar, I don't know if you have any experience doing this, cost of operation did not change, that I noticed any way and the quality of installation was fine. T Boone Pickens' plan is to run all trucks on natural gas, "HEAVY DUTY AND LONG RANGE VEHICLES" can not use E-85 but can use natural gas. So I don't know what you're talking about maybe because you don't.

What I'm talking about is your question in your first post asking why Ford doesn't offer CNG conversions. The answer is that they once did, demand was low, and range limited.
The aftermarket problem (emissions) is not answered by you claim that yours was "fine." I somehow doubt the EPA will take someone's word on that.
And here's a suggestion: if you don't want people answering questions you post online, don't ask them.

Its always wayyy to little and Wayy too late for the Wayy too bIGG 3... they cannot grasp the concept that people want a reliable quality vehicle.. they have made a few steps to make a futile attempt to compete, but they never built cars that could compete with the real 3 Toyota Nissan and Honda.. Saturn was just a advertising promo that was the crap GM built with Fiberglass doors and a stupid looking front end but the parts fell off or apart way too early and even an oil change was soo difficult that you would risk serious injury trying to change it... yet the whole time GM was trying to say that it was going to be a totally new car and new company from the ground up, when all they did was create a new division that would replace Oldsmobile... just like all the other GM products they are the same vehicles with a slightly different dress and minute differences on the interior... yet the problems were that management gave the employees poor designs to build this junk and the Unions thought it would be a great idea to make sure that every other parts plant would go on strike to make certain that problems would always occur on serveral parts on every vehicle they make... they never learned... the management thinks its a wonderful day that they deliver 1 extra MPG buy giving you less car and the Union takes great pride in making sure that its members will get themselves laid off by asking for too much money and then undermine the quality by going on strike... yet Rick Wagoner thinks its totally great to take Millions in bonus money will GMs stock tanks 200 percent in 1 year... Yet Toyota, Honda are here building better cars in America and the Unions watch all their jobs go to Mexico because they were too stupid to sit down with their employees and management and cut a realistic deal to keep their jobs here and their retirement in good standing now the mafiosos are going to squander the $35 billion that GM gave away.... this tragedy is soo stupid that its soo hard to ignore since its a train wreck that is happening and once its over all these prideful morons will still tell the employees that they did their best in taking care of them.... A CEO once said that he was not serving his employees well if he overpaid and over hired to run a company into the ground and had to have massive layoffs and relocate overseas to save the company... he said that if he did that then he did not deserve a bonus and probably didnt deserve a job... the Management, Union leaders and employees who thought that GM FORD and CHRYSLER soley existed as an ATM with unlimited Money to fill their pockets should be sent to a Soviet Style Gulag and crush rocks in the winter in Siberia as punishment for the mistreatment of good workers and the dealerships and the suckers who bought their inferior vehicles... They should have offered more fuel efficient versions of thier vehicles for those who wanted to drive a truck or mustang etc but didnt want or need 500 HSP under the hood, they could have made 4 5 or 6 clynder engines with great gas mileage and those who wanted to burn gasoline for no real reason should have been given the option to buy those and those who needed a truck for real work then they could have bought a fuel efficient turbo diesel instead of the largest diesels possible as the only option or biggest gasoline engines possible... I cannot understand how Toyota can build a Toyota Avalon that gets 20-30 MPG with a 6 cyl engine Yet Ford and GM can barely get 20 tops and celebrate this as if they are doing everyone a favor.... Its a Shame

Are we suppose to feel sorry for the suits that went on there little shopping spree buying up all these co.s ? i.e. mazda,daewoo,saab,jag.,a.martin,opel,to name a few.