took my Z out for a spin the other night. It ran fine for about 5 miles, then after I stood up on it a little it went lean on the AFR gauge. So I limped home. let it set for a bout 5 mins. then started it back up. It did fine for a minute then went right back to lean again. Tonight I scanned it and it said the left O2 sensor was lean(go figure) I pulled the injectors and cleaned the fuel rail out reinstalled it started it it and it seemed to be doing fine The gauge was going to rich when I crack the throttle and then to lean on decel and idle in between like its supposed to be. went for another trip down the road. ran fine just cruising then when I got into it a little it went lean again. Back at the shop SES light on again,scanned it again, same code again. still running lean on the left bank. Suddenly the AFR guage says its running right again. Thats where I left it tonight. What can make it go lean under hard load on one side? I checked the fuel pressure under load and it holds steady so that rules that out. Clogged injector? Blown intake gasket? What do you guys think?

 

Try and run the engine with the o2 sensors unplugged and see what that does.

 

Maybe you have a bad injector, bad O2 sensor or a wiring issue. You could swap the 4 injectors into the other side and see if the issue follows as well as the O2 sensors also.

 

Exactly what code do you get when the SES light comes on?

 

Check for leaking intake gasket on that side by spraying carb cleaner and watch your exhaust for alot of white smoke. That's how I found my leaking intake gasket. Also if you spray a liberal amount you can also watch for bubbles coming out as well. Sounds like that may be your problem. Let us know

 

Fred it gave me a code 44 left oxygen sensor lean I did spray carb cleaner around the intake and listen for the motor to pick up but nothing

 

almost sounds like a defective o2 sensor with it only being on one bank or possibly an exhaust leak too

 

The code sets when the long term fuel corrections max out, and the O2 sensor is still telling the PCM its lean. Even though you only set the code for one bank, a data log would tell you if there is also a problem on the other bank, that just hasn't reached the point where it sets the code for that bank. If you know whether its a problem on one bank or on both banks, it might help you determine whether its a true lean condition, or a "false" lean.

Is your A/F ratio gauge the one that uses the stock O2 sensors? Do you have it connected to one bank or both? Is there a possibility the connection to the wiring or the gauge itself may be causing the problem?

 

The gauge is a Autometer Im sure it is for the stock O2's The car does act up when it says its lean so I dont think it is a false reading. But it is only hooked up to that one side so I dont know if both sides are running lean. I just want some advice of how to troubleshoot this thing and where to start looking for a problem. how can I test the injectors to tell if one is faulty? both of the o2 sensors are fairly new.

 

i'd also check your tune