I've gotten my exhaust done and a full tune-up except an oil change. When this was first done I got a good est. 25 mpg in the city. After that ran out its back to the same problem whcih is like 13-15 mpg. My only suggestion could be my air intake which is not a K&N, its some bootleg **** and I do have a heat shield made out of 3 layers of that bubble wrap. Could anyone help me with this?

what'* your LTFT? what'* the O2 saying?

what is LTFT? I changed my 02 sensor too.

You changed the O2 during the tuneup, So it'* probably vacuum related.

Am I the only one that thinks getting 25mpg in city driving is impressive?

yeah I did try to change the rubber vacum fittings because they were craking and its hard to them on and I didn't put the new ones on all the way. Is there a trick to getting these on?

push and turn.

Push then offest and rotate, keeping the same offset. Like you're cranking on a handle.

isn't there a different size that goes from the FPR to the vacum blcok thing? because the FPR stem is skinnier than the other stems and thats the one thats kind of loose. I used 1/4 rubber fittings for the other three is this correct?

With a 3.8 yes it is good.
Even for highway mileage it is not "real" bad.

I changed the rubber fittings correctly and I'm still getting poor mileage . Could there be anything else mechanically wrong related?