How much will a stall kill mpg?

[BlownStangGT]

I know I know I know, why do you have a mustang if you are worried about mpg, Im not, but Im just curious how much would a 3000 stall, lockup, kill mpg on street driving? Right now I get 18-20 street driving. Thanks, still learning the auto thing

 

[89rdgt]

well if its a lockup converter its not going to make a diffrence on freeway driving because itll just be locked up. City driving you might notice a decrease from stop light to stoplight. not exactly sure about how much though.

 

[notchback]

agreed...not much

of course if your romping on it from stop to stop all day long,a lot.