Bad Gas Mileage After Top-end Rebuild

[Bill2001gt]

I'm a newbie so excuse me if i sound lame at times.
I have a 2001 GT convertible I had a whole top end rebuild $4,000 , my gas mileage went from 16/17 down to 13/14
Started reading blogs and have cleaned my mass air flow sensor, new air cleaner , new plugs, 4 new O2 sensors. Checked for brake drag, they did put on new timing gears and chains and tensioners on could they have missed tooth or 2 and cause bad gas mileage. The car runs and sounds great. Any experienced help appreciated

 

[Bill2001gt]

 

[Modular2v]

You paid 4g to have the top end rebuilt??? OUCH

Could it be that you are driving with a heavier foot?

 

[Bill2001gt]

Thanks for your reply I feel the same way about the cost in answer to your question about the heavy foot know I've been purposely keeping it under 2000 RPMs and the gas mileage still stays about thirteen and a half where I used to get 16 and a half to 17 I did take a road trip and got 19 on the highway where I used to get 23 I put all new air cleaners fuel filters clean the mass airflow sensor All 4 new O2 sensors new spark plugs new intake manifold
Should I just live with 13 and a half to 14 miles per gallon and call it good or keep looking for Solutions

 

[Bill2001gt]

I should add that I live in the Palm Springs area California and the temperature has been in the triple digits and the air running all the time but I've had the car for 3 years and drove it through Summers the same way

 

[Modular2v]

Hot air is definitely not helping. Have you disconnected your battery for awhile and let the computer re-learn?

 

[Bill2001gt]

Haven't tried that.......thanks
How long disconnected ???

 

[Ogre]

5 to 10 mins should do it.

 

[Bill2001gt]

thanks

 

[Bill2001gt]

I blogged it and it said give it 3 or 4 days to relearn the new settings so I'll let you all know what happens.

By the way if any of you Mustang owners have rattles that sound like it's coming from inside the dash and you can't figure it out and it's driving you nuts check the sun visor clip brackets make sure they're tight. I swear it sounds like it's coming from right behind the AC vent but it was a sun visor clips that were doing it what a relief to find it

 

[Nemethjames1]

Damn 4K I would have done prison rings and other bottom end stuff if I charged a customer 4K. Should have just bought a used dual overhead cam for that!!! Lol, but reset computer, check for any vacuum leaks but really a small vac leak wouldn't account for that much of a drop!

 

[Bill2001gt]

Thanks, I did the computer reset and I'm giving it a few days. I thought about the used engine thing but didn't feel I had the expertise to pick out something used that I wouldn't have to do the same thing too after I bought it.

 

[Bill2001gt]

One+ about the battery disconnect is that I was having a intermittent ABS light also and it's been clear now for the last 2 days. More will be revealed

 

[squeak93]

Keep us posted on further findings.

 

[Bill2001gt]

Had my tires rotated balanced and inflated to 38 pounds still only got 14 .3 miles per gallon on the last tank. I'm thinking about new coil packs any suggestion where to go from here

 

[Bill2001gt]

Check gas mileage this morning it was 13 and a half miles per gallon. I am trying some seafoam in the gas to clean the injectors but I am running out of options. Does anybody think they could get the timing off when they rebuilt the top end, they put in new timing gears chains and tensioners on it runs really well butt smells like it's running rich any help would be greatly appreciated

 

[jeno_labanca]

I would say its the top end is off like the timing

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[Bill2001gt]

Will the car still run strong.? Also there is a slight murmur or skip at idle. Thanks ...

 

[jeno_labanca]

The skip at idle is probably a misfire

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[Nemethjames1]

Pull the valve covers, set crank pully to top dead center, and verify both cams line up to the proper marks. That is horrible gas mileage, with my 4.10's and stock 04gt I get 18mpg average, and that is full throttle half the time i am driving if not more, and I red line it everyday