milage getting worst after the maintenance

last week, i have changed the distributor cap/ rotor, vacum lines, muffler, also checked the air pressure in tires, greased front end cleaned MAF and Throttle body etc.

I was expecting a better milage than before, it was doing 123 miles with 3/4 tank, now 108 miles with 3/4 tank.
btw. I have K&N in box filter.

What would be the reason? gas is 3 times expensive in here ( 10$ a galon approx.)


I have installed 98+ front end but I didnt changed radiator core support ( due to low budget ) would it be the one of reasons? ( air box inlet is behind the headlights and it might be blocked?)

Could have damaged the MAF while cleaning it.. Doesn't the MAF fail to a rich condition when it dies?  

Would you not get a Check engine light if the MAF dies?

I have access to proffesional test device, I can let it checked. But I cleaned maf with breake celaner, i didnt touched the diods, washed with breake cleaner and air dried ( kept the gun 15-20" away from the diods).
 
Any other ideas?  

I think you are right, the check engine light should comes. Once I forgot to plug its connector back and started the car, and engine light showed up.

A quick google search shows quite a few people that have ruined MAF sensors by using brake cleaner on them.  CRC actually makes MAF sensor cleaner, but any computer contact cleaner is what you want to use.  And the MAF could be killed and not trip a code...or just become essentially useless for metering air, but not be fully dead yet.  Then it wouldn't trip the code, you would get the rich condition, poor mileage, etc.

But other than a MAF, it could also be a blocked intake...did you swap front ends at the same time as the rest of the tune up?  Also how many tanks of gas have you run through since the tune up?  The computer may just need time to adjust to the new parameters with properly functioning equipment now!