ok i put headers and a catback, a 350, open element cleaner, and injectors from a 350 caprice, ever since then ive been getting 11 mpg on the highway, and thats with timing that will keep it running...heh...without stalling out so the timing is correct, whats wrong with it

Got any vacumn or fuel leaks?

I get 6 city, and 20 highway. Go figure.

not that i know of....damn this blows

What are your engine specs. You may need something different than the caprice chip. Your torque converter may not be locking up either. run winaldl if you can and pull some data from it and go from there. Are you getting any SES codes? Those will hurt mpg as well.

Well my brotherrs 350 in his 91 caprice does the same thing and it's stock like that. he gets better city mileage than he does highway...as a matter of fact he get 12 on the highway and about 18 in the city. go figure...though he does have a bad MAP sensor.

Damn. somebody got a heavy foot?

i get 10-15 city and 20 highway. i would have to try very hard to get 6 in the city. hell it takes a half tank of street racing to get 10....

its just a damn 350 rebuilt whatever i think their lb9's or whatever, i dunno i cant remember right now, i think it might have something to do with my timing advance, its like the stock timing wont run, at all, for even 2 minutes, so i got it advanced...alot...alot alot....thats about it, where can i get winadl???

check your spark gap. if it's closed up too much you'll will suffer horrible fuel economy