yes, it's a scam. I don't have to know the rest to confirm that, simply because they are once again pretending paypal is something it isn't!
The paypal emails are fake. The scammer does not have the car. The "shipping company" is actually the scammer or an accomplice, and if you send money via western union, there will be absolutely no way to recover it.
Incidentally, Paypal is not an escrow service. They do not have any kind of program where they hold money back until something is done. If the money is there, the transfer happens instantly. The buyer protection programs are like credit card protection--i.e., the buyer can request a refund after the fact. Paypal also does not support any transaction that involves sending money via another service. They make their money by collecting fees for transfers--they are not going to help you to pay that money to another service instead of their own!
When questioning a paypal transaction, you can also forward Paypal emails to
[email protected]--in general they are pretty good at responding to confirm whether the email is fake.
Incidentally, African scammers love to threaten to contact the FBI, and they even love to send fake threatening emails from the FBI. That's because they really have no idea how our system works, and they think FBI sounds serious and threatening. The truth is, the FBI would not be involved in a simple case like this involving a small amount of money (and 1500 is small to them)! If mention of the FBI comes up during a transaction with a stranger, you are probably dealing with a scammer.
Can you please post the emails you received from the scammer (with your own info removed)? Having the scammers script, email, and other info posted can help to prevent others being scammed.