12.8 MPG wth ?

[Codfish]

Here's the deal, I dont know if this has something to do with it ...

Lilqik, Marvin (his bro), and I re-built this engine. It runs well on acceleration, however when cruising at (for example) 30mph it has a stumble kind of like I just washed the engine. Not extreme as that but it has a slight hesitation. While in park when I try to keep the the rpms at 2000, it moves to 1800 then back up and down slowly...So I said let me check my mpg's.

To test the gas mileage:
I filled the tank and drove 100 miles and refilled the tank and it took 7.8 gallons.

100miles / 7.8 Gallons = 12.8 mpg

So I did it again

100 / 7.9 = 12.65 mpg

What the hell ? Any assistance would be appreciated, I don't know if this makes a difference but, I am in the break in period for another 200 miles

Here is pic of the ride...

Here is the build...

http://www.facebook.com/media/set/?set=a.254449737901421.73998.100000091898463&type=1&l=40dbe90087

 

[QWERTYphoon]

Re: 12.8 MPG wth ?

check your rockers to make sure they have not come out of spec. I had similar problem.

 

[TYTILIDIE]

Re: 12.8 MPG wth ?

It kind of sounds like its trying to dump fuel. What all was done during the build? I don't have Facebook. What is your set up as far as a tune goes?

 

[BoostedSUV]

Re: 12.8 MPG wth ?

All I ever get is 13mpg so I don't know if that means anything but what's your fuel pressure set? Check for a vac leak on the line to the regulator.

 

[jimmyz79]

Re: 12.8 MPG wth ?

Check your plugs...
Check your ignition (cap rotor wires)...
Check for a vacuum leak...