Does anyone have an idea what could be causing this? My car always passed emissions, now it won't. Check engine light comes on after 30 miles. Runs and idles fine. Service tech said light is triggered on de-acceleration. A smoke test was performed up front with no vacuum leaks found. Plugs were changed two months ago. Fuel pump and sender replaced about two years ago. I tried researching this on the forum with success. Your help greatly appreciated!

 

I think you have bad cats., or bad O2 sensors..!

ZAYED,,

 

My 02's were replaced on the side that is coding up. I was told that bad cats cause drivability problems which i don't have.

 

OVER THE WEEKEND CHECK ENGINE LIGHT WENT AWAY WITH ALL READINESS IN SCANNER SHOWING OK.....

 

Mine has had these codes since I started modifying my car about three and a half years ago. Mine also does it on decel. I watch my DashDAQ to see what causes it and it happens when coasting/off the pedal for several seconds. The short term fuel trims will jump from 0% to around 17% after several seconds of coasting. Once on the gas again, they jump back down to normal range, but that brief time is enough to trigger the "lean condition" code.

 

My car has been fully modded for years without problems and I always passed emissions. My shop got the car a told me the ecu stored a code that read, 02 beyond threshold, so they replaced the 02's on that side (driver's I believe) with no success. My check engine light would pop up after 50 miles. This weekend I did a TB reset and disconnected the battery for a few hours and that did the trick, no more check engine and all readiness is showing ok in OBD II scanner. Just like the movie Cristine, I think my car knows I want to sell her, and she is pissed off!