82 231V6 Dualjet carb E2ME-gas mileage

I'm trying to get a little better gas mileage with my 82 231 V6 with CA emissions ECM control.(It is actually a Buick engine). With the stock engine (rebuilt) it runs just fine but I'm only getting 8-9 mpg around town (lots of short trips) and about 15 mpg on highway trips. I'm thinking I should be getting more with 6. It did about the same when it was new, I've had it since 83.

I've been through all the vacuum hoses and checked for leaks, replaced most of the them. I've put a dwell meter in the passenger compartment connected to the green connector near the carburator to see how the ECM operates. Here's what the dwell does:

When cold at start dwell is 0, choke opens in less than minute and it goes to 10.

As it warms up at idle the dwell goes to about 30. Step on the gas and it momentarily goes to 10-20. Just cruising along it stays between 30-35.

As it gets hot the dwell starts climbing to 40 and above, and after a long run it will be idling and cruising with the dwell above 50-55.

Wondering if this is the correct dwell mapping for this car. It seems logical that with a higher dwell on long runs that I should be getting better mileage.

However, is there any way to get beyond 15 mpg with this car, or am I chasing my tail.

Any suggestions,

Jerry

damn, something is up. Have you checked all the small things? Distributor, spark plugs? my old 305 with huge racing carb got like 10 mpg, no reason for you to be getting that with a v6.