ok im getting really bad mileage!!! it had new plugs and wires and stuff before storage but over winter i put all new exhaust on, now i am getting bad milage... would it be running rich? smells it a little but not much.
i have an o/r h would new o2 sensors make the milage change? i drove really easy today, shift at 2000-ish, except for the odd shot i gave it up to 4 or 5 (not very much) and i got 12.2 MPG cant be right...

 

have you tried disconnecting the negative battery cable to let the ECU clear the KAM (keep alive memory)? try this for 15 minutes and then reconnect it and see if this helps any. I didn't have this kind of problem with mileage when I put on my off road H-pipe and I reused the original stock O2 sensors too. if you still have the original O2 sensors, maybe they are worn out and new ones are needed?

 

ill try this and then ill replace them if it doesnt work..but roundman you are one of if not the most knowledgable people on this forum and i have been having a lot of trouble with my car lately ill type the whole story out for you and send you it would that be ok? do u have an email address i could use my PM's dont work

 

just click on the email icon under my last post and I should get it that way no problem.

 

12.2 mpg? i would have loved to have gotten that a month ago. i was getting somewhere around 5-6. i changed, plugs, rotor, and cap and it didnt help it. i live about 20 minutes from work and it was taking me about 1/8 tank to get there and back. if i was riding around i could just about watch my gas guage drop. i changed my 02 sensors, o2 harness, maf, and a few adjustments and it more than doubled my mileage. not exaclty sure what its getting now, but id guess its somewhere around 15 or so.

and i agree with you about roundman, he is very knowledgable about mustangs. think im gonna add him to my christmas card list.

 

yeah check to 02's and for vacuum leaks..

 

What's a guy gotta do to make your Christmas GIFT list, that's the most important one, right??? LOL

 

5-6??!?!?!!! That is horrible. Are you driving with your brakes on? lol. I have read that the computer in the late model 5.0s are one of the best computers that a car can have. That is why we can add so much to the car without having to flash the computer or add a chip. The computer can create new numbers to accomadate the add ons. So I would try disconnecting the batt then reconnect.

I think I should do that too.

Oh..by the way...I get 20 mpg with a least two hard take offs a day. It is stock but adding components like exhaust and intake should free up restriction causing better gas milage. It starts to get worse when you have to up your injectors and fuel pressure...more fuel more power....more fuel less MPG

 

wow 5-6...damn my friend with a 7 inch lift 35 inch tires and a 400 cubic inch engine get like 10....and thats because of all the **** he has...damn that would suck

 

i was getting 18-20 before storage and before i put the exhaust on, but the local mustang guy has my car in for an apointment on tuesday so i am hoping for the best!!!