Greetings to all !
I just had my 1991 300ce in the shop for a headgasket job and it seems to be burning more gas than before now. !
It seems to give me 11 miles per gallon just driving around town ,
that seems very bad and I did not have this problem before the work was done ,

any ideas of what the problem could be ?
you're input would realy help me .
thanks.

What were you getting before ?

Any other info on work done along with head gasket?

thanks for you're reply !

yes the time chain was replaced as well , spark plugs replaced , added a K&N air filter also

The mileage I was getting before the Head job I am not sure about , but I know for sure it was not 11 miles to the gallon .

if something was done wrong from the mechanic what could it have bein ?

My bet is you have the wrong spark plugs. There should be no other reason why it would drop. Pull one out and see what type of spark plug he put in there. It may also be a good measure anyway to make sure after the head gasket swap everything is showing up fine on the plugs.

I will check that out !
I think I went with the NGK platinum plug
I hope that's the problem and it does'nt escalate to anything bigger .

You want non resistor copper plugs. The platinum plugs are not the correct ones and are designed for the much newer cars with the high capacity/ voltage/ whatever ignition systems.

Change your plugs.

I personally don't think that is the problem, but it solves one thing that is wrong.

Well my mechanic called and said he could not find anything wrong with the car ,
he said the timming is right ,and that everything is working properly ,
I heard that a bad exaust system could also be causing this.
He said that if it were the exaust system or the catalytic converter the exaust tips at the back would be firing very uneven ,wich he says is not happening to my car.

Get the plugs changed man!

If all of a sudden your MPG dropped its not gonna be anything in the exhaust system....I'm surprised he even said anything like that.