Running a bit lean at idle, idle surging, lc-1 intermittently reading 7.4

[4gfun]

My car recently started running a little bit lean at idle (A/F Ratio 15.0-16.0) where before it used to sit nicely at stoich hovering between 14.7-14.9. I am also now getting idle surge suddenly. Before this all happened, my Innovate LC-1 Wideband gauge was flashing 7.4 for a few hours. It runs just fine for about 30 seconds in open loop until the sensor warms up.

The Wideband is setup to simulate a narrow band. The wideband is mounted in the stock O2 location and only has about 9k miles on it.

Is this a dying O2 sensor or LC-1 module possibly? I can run a BLT test but wanted some ideas before I did so. Last BLT test was run only 3k miles ago and I fixed all leaks at that time.

I am going to tackle the fuel filter first because it needs to be changed and wanted to rule that out as a cause of running lean since I have one handy but that wouldn't be causing the idle surge.

Thoughts?

Thanks

 

[92AWDHX40]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html




this for your idle issues.

 

[4gfun]

Good links, have read them in the past and will go down that route for sure. I am a little bit suspicious of the O2 sensor reading 7.4 though. It hasn't read that way since the problem started but still. I guess it is cheaper to proceed with those methods again along with a BLT since it isn't my daily.

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)

http://www.dsmtuners.com/forums/articles-engine-fuel/191137-how-fix-your-idle-surge-problem.html




this for your idle issues.

Vacuum leak yessssssssssss!

Turned out to be a 3 way tee that I used in place of a normal vacuum connection. Used JB quick to plug it. Guess it got sucked in !