By Emory Bryan, The News On 6

TULSA, OK -- First it was the government running on empty with the Cash for Clunkers program, and now it's car dealers who are running out of cars.

It's not that dealers don't have cars, but they're running short on available inventory for the clunkers program.  A Ford Focus and Escape are about the only two left on the lot at Bill Knight Ford.

"That's our biggest challenge is trying to get vehicles in.  Our focus is really cars that have been built or ones at the ramp ready to be delivered to us," said Bill Knight.

And, it's not just Ford.  Chevrolet dealer Jim Glover says he normally stocks 800 cars and now he's down below 200.

"Well, we're picked over right now.  We've got 400 coming.  We've got a lot pre-sold.  When they come in, the sale staff calls the customer and tells them the customer their car is here," said Jim Glover.

Like Ford, Chevrolet has plenty of models that qualify, but the factories are behind on building them.

The Cash for Clunkers program can make or break a dealer.  It's selling cars, but it's also creating a financial burden.  That's because the dealer is essentially extending credit to the government, $4,500 for each car and none of the dealers are sure when that money will come back.

"We have not been paid yet, so far we've done 100, and many of those have been submitted.  Many are under review.  Some have been rejected and none have come through, so we're working through that," said Bill Knight.

Knight isn't worried about getting paid eventually and neither is Jim Glover.  It's just another unanticipated side effect of the program.

"The government is, you have to dot every I and cross every T, but that's one customer I'm not worried about paying us.  We'll get our money," said Jim Glover.

Both dealers say demand remains strong, at least strong enough to run through the extra $2 billion in the program.