Rep Power: 0

I have a 1997 Honda Civic LX with a D16Y7 engine. So I have the check engine light on for the code P0170 and a couple other that all deal with the fuel system being too lean. So far, I have already replaced the fuel injectors, fuel filter, and pcv valve. I still have the light on for that. Before even when the light was on I could get 30 mpg, now I'm only getting about 25. Do you have any suggestions on potential causes of this problem? I have also used a couple of fuel system cleaners. Let me know what yall think. Thanks.

 
Rep Power: 517

P0170 should not be found in that car.
I'm not sure you can trust your code reader, you may want to try a couple other brands and see if they all agree.

Please list all of the codes.

 
Rep Power: 210

How many miles are on the current oxygen sensor?

 
Rep Power: 0

Both the upstream and downstream sensors have only about 3 or 4 thousand miles on them. I heard something somewhere that a cracked exhaust manifold could be a problem for a lean condition because more air might get in, so I am going to check that. But I replace the exhaust manifold less than 7000 miles ago, but it was a cheaper one.

 
Rep Power: 0

I don't remember the brand of the code reader, but it was one that an employee from Autozone used to find the codes. The other code was P0171.

 
Rep Power: 0

Also, the boot that the airbox attaches to the throttle body is a kind of cracked, could that be a problem?

 
Rep Power: 517

P0171 is the lean code.
P0170 is not a possible code from that car, that's why I don't trust the code reader used. If it lied about this code, why should I believe the other code?


If possible (all but the cheapest code readers will give this), write all of the freeze frame data that is stored along with noting which fault code it belongs to.

Not related, can't cause the code on that car.

What brand sensors were installed?


Did you get a tankfull of E-85 instead or real gas?
Check fuel pressure?
EGR passages clogged?