exhaust leak

l have a 95 F150 with a 302 cid it only gets about 13 mpg would an exhaust leak at the manifold cause it to get such lousy mileage l've changed the plugs air filter an EGR valve l'm not getting any codes but i'm not getting any gas mileage eather .

l have a 95 F150 with a 302 cid it only gets about 13 mpg would an exhaust leak at the manifold cause it to get such lousy mileage l've changed the plugs air filter an EGR valve l'm not getting any codes but i'm not getting any gas mileage eather .
no the exhaust leak will not cause bad gas mileage, have someone set your timeing or do it yourself that will help you gas mileage problem.

A manifold leak can affect manifold vacuum. It can also cause burnt exhaust valves.

If the leak is beside an o2sensor it makes the sensor think the engine is running lean and the computer really sends more fuel. A bad thermostat will cause bad mileage.
Air leaks around the intake manifold causes problems. Spray carb cleaner along the edges if leaking the engine will run better.

fixed leak made no differance. But l got to thinking how it was acting with no power an all so l checked the timing marks an no highlight l fig a motor that had been changed 60000 miles ago would show signs of high lighting so l moved the dist' a little. made all the differance now have plenty of power at take off an driving. now l need to set it with a light to get it rite.
Thanks for all the replies BA