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Old January 19th, 2007, 04:19 PM   #13
Covered in mud...
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Join Date: 11-06-05
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Originally Posted by Gr8wht2000GMC View Post
what i cant understand is how it cleans up so suddenly and runs like a awesome beast until i start it the next time.
Originally Posted by ScOoTeR View Post
You have a massive airleak or fuel restriction somewhere. You're running wayyyyyyy lean in open loop - coughing and popping are a good sign of that, also the lean codes are from the ECU having to compensate for the lean condition.
Originally Posted by Yetti View Post
I too can only guess on this system. one of the things that comes to mind is your ECM maybe having issues with the open loop function. I am wondering if you have a bad injector or TBI Gasket is sucking air on one side real bad making a lean condition until the computor makes it to closed loop...
I'd try hunting this down.

Open loop is generally during start up, and heavy throttle up around 70% and higher.

So, at stat up/idle, it'll run like ass.

In closed loop, it'll compensate for it pretty well.

In wide open throttle, you might be running lean and not knowing it. In fact, you might be happy getting more power and/or better mileage. Factory calibrations are generally based on SAFE operating conditions. There's almost always power/mileage to get had by leaning a motor out, at the risk of detonation, etc.
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