Leaning Out

[1fastRS]

I wasn't sure where to post this, because its a 95 n/t, but I can't find anything in that section, and does have to with tunning. Anyways, I have a S-AFCII and I've been leaning it out a little to gain some power, since it comes very rich stock. I've been running around a low 13:1 a/f ratio ( i have a wideband ), and everythings been fine. Now all of a sudden when I'm driving it will just go lean for now reason, and I'm talking like a 18:1 and higher. But I have now idea if its an electrical problem or if its part of the fuel system. If I put the gas to the floor, it will come out of it, but when I get off of it, it will shoot right back up to lean. This will only happen once in a while, but its becoming more frequent. Also if I put all my settings back to stock, it will still do this. This makes me think its part of the fuel system. But I'm also leaning towards it being electrical b/c if I shut the car off, and restart it, it will go back to normal. Also I put my data logger in, and noticed when it goes lean my long term fuel trim goes down to a neg. 20. But it dosent pull any timing. Does anyone have any ideas on what this could be? I'm going out to check the voltage on everything, I just changed my fuel filter not too long ago. I changed my plugs yesterday, and my fuel pump sounds perfectly normal. If its not the ecu, I'm thinking maybe its the injectors. If one injector was going bad, could this happen? I wanted to get some ideas before I start tearing everything apart, and replacing things. Please help.

 

[timloomis]

your car will lean out when your off the gas.dont pay any attention to the afr when your foot is off the pedal.the ecu goes into open loop on a decel.

 

[1fastRS]

I already know that, thats not the problem. The car is going lean, literally. You'll being driving along, and bam, the car starts to lean out, and it beggins to bog, and sputter, do to the lack of fuel. Its not a good situation, but it hasnt blown up yet, so thats good.

 

[ITSME4G63]

if its boggin and sputtering due to lack of fuel why dont u richen it up with teh afc