Can that be adjusted? My car is "boffing" and "poffing" at idle (950 rpm, 1100 when AC is on).

It also missfires when I lift of the throttle at 1500-2000 rpm.

I think it runs to lean, I have a autometer A/F guage and it is showing no lights at idle exept after a "boff" and then it just blink a little at 5-8 leds.

The car is total oem.

 

Without seeing what mods/ecu you're running, I would say you're probably running too rich, not lean. That's why the car stumbles at idle. Best way to fix that, programmable ecu. Also if it only happens intermittently, it might be a bad air intake temp sensor.

 

He is running stock (total OEM).

I would think that you would want to do a tune up. Definitely the plugs and wires would be a good start. Air filter, oil change...see where that gets you.

A little bit of back firing seems to be common, even on stock FDs, and probably won't hurt anything. When I was stock, there was almost no back firing at all. If it is really troubling to you and the above maintenance items don't help, then you will need to look further (air adjustment screws, O2 sensor, etc.).

The Autometer O2 gauge will tell you next to nothing (under load). You really need a wideband for your car.

BUT...maybe some of your issue is associated with the O2 sensor. At light load the computer uses feedback from the O2 sensor to lean out the fuel mix (for economy). Potentially your O2 is tired. Maybe that is why you are not registering anything on your O2 gauge? A bad sensor may also cause the computer to add more fuel when it shouldn't...this may cause back firing and stumbling at low load.

Hope this helps.

 

I am getting a clean rich indicating at high load, at low/average load it bumps up and down so it looks ok. if it would be rich at idle I would se it at the AF meter I think, Cause I se then it goes rich at bouth closed and open loop.

I will try the plugs and change oil and se what that gets me.