http://www.imcdb.org/movie_397306-American-Dad!.html
There are from all the episodes that are currently on DVD.
Some of these cars may be generic and just not resemble anything (therefore wont need to be added), but i though id put em in there in case someone with a better eye could see if they did look like something.
Season 1
Ep 1.15
Unknown Limo - 1 Star


Ep 1.17
Blue Car, Honda Insight or GM EV1? - 1 Star

Cadillac XLR - 1 Star


Ep 1.19
Francine's Car, Unknown - 3 Stars

Geo Metro? - 2 Star


1.20
Hummer H2 Stretched Limo - 3 Stars


1.21
Dodge Ram Van - 2 Stars

Jeep Wrangler - 1 Star

Pontiac Firebird - 2 Stars


Season 2
2.01
Chrysler 300C - 3 stars (Used in a quick remake of a terminator 2-esque chase scene)


2.03
Unknown Sedan - 2 Stars

Unknown Convertible - 2 Stars

Unknown Coupe - 2 Stars

Unknown Sedan - 2 Stars

Unknown truck, Peterbilt? - 1 Star

Porsche 356 Cabriolet (headlight are wrong but its definitely a porsche) - 2 stars


2.04
Saab - 1 Star


2.07
Unknown Bus - 2 Stars

Unknown (supposed to be from the future)- 1 Star

Unknown Pickup - 2 Stars

Unknown Van - 1 Star


2.08
Unknwon Hearse - 1 Star

Ferrari testarossa - 2 Stars


2.12
Made For Movie (for comments since animated Made for Movie cars aren't allowed) - 3 Stars


2.15
Ferrari F50 Spyder - 2 Stars


2.16
HUmmer H2 SUT - 2 Stars


2.17
Rolls Royce Unknown - 1 Star


2.19
Harley Davidson Unknown - 2 Stars


Season 3
3.02
Mercedes Unknown - 1 Star

Westward Go-4 Interceptor - 1 Star


3.04
Chevrolet Corvette C6 - 2 Stars


3.05
Hummer H2 SUT Stretch Limo (Slightly different to the other one)- 3 Stars


3.07
Nissan Titan - 3 Stars