My car had been sitting all winter and I recently started driving it again. After going threw a couple of tanks of gas, my gas mileage is consistantly less than it normally is. I use to get about 23 MPG (mostly highway driving) and now I'm getting 17 MPG (same highway driving). I put in a new O2 sensor last summer as well as plugs and wires. Other than it seems to be running ok. I don't smell any gas, so I'm assuming that it isn't leaking. Could the injectors be leaking? Any other ideas?
thanks,
Chris

 

Might want to change the fuel filter. Low pressure will ruin the injector spray pattern and waste fuel. If the filter doesn't help, could be the pump.

Or, could be leaking injectors.

 

I checked the fuel pressure and it was ok. It also held the pressure for a while after the pump was off, so I don't think the injectors are leaking. Could any of the injectors just be injecting too much fuel? Is that possible?

 

I was reading another post awhile ago and the guy had the same problem. as it turned out someone was stealing his gas, just a crazy idea; I'm not really awake yet

 

I've had it in the garage, so I don't think that is the case...but thanks anyway.

 

Have you checked the pressure while driving?

It is possible for dirty injectors to not leak and have a poor spray pattern.

 

I rechecked the fuel pressure and now I found that is dropping off rather quickly after the pump turns off. It will go from 45 to 20 psi in about 30 seconds. Then it takes a while for it to get down to zero. I don't see any external leaks, nor do I smell gas. This sounds like a bad injector, right? or could it just be a bad regulator? I guess my next step is to remove the fuel rail? I've read that some of the stock injectors are very poor. Is that all stock tpi injectors? I have a set of 22 lb injectors from an L98 and 24 lb injectors from an LT1. How do these compare?