I'm doing 17.3 mpg with the computer tuning (the most visible is the 1100 rpm idle, not sure about the fuel curve). Is this normal or too low? Thanks..

 

Probably about right. I'm getting less - but I just had the motor installed (haven't really had time to run the car much), the program is new, & I might have bad O2 sensors.

 

does it need to idle that high?

 

I have the HOT Cam and my idle is 900 rpm's set by Ed Wright.

 

i thought that was alittle high

 

My hotcam idled at 900 rpms with tuning from pcmforless and it was fine there. I got 27mpg highway with my hotcam, not sure about city, I don't remember.

 

See the deal is if you have a Torque converter, the idle will go down. I don't have one yet so my idle is still 1100 (Ed Wright).

Do bad O2 sensors cause such bad gas mileage? Thanks..

 

Not positive, but I had a mechanic tell me that O2's are only good for 50k & they can cause alot of things.

 

It depends on the generation of O2 sensor, some are 30k some are 100k. The 4th gen FBod sensors fall in the 70k-100k range, with 100k advertised, but with an exaust leak or something like that will shorten the lifespan.