What on our trucks provides an extra amount of fuel when you first increase your throttle position to keep from going lean at first? Whatever it is, i believe that it is broken on my truck. Whenever i smack the throttle, my AFR reads as low as 18 or 20:1 for a split second and then it heads up to around 13 then back to 14.5 or so if i hold the throttle. I have recently replaced the TPS and the MAF has been cleaned as well. Any ideas?

 

Thee ECU makes it happen, it makes the decision based on input from the TPS, MAF, front O2 sensor.

Is this reading coming from your wideband? I'm pretty sure it's normal. It'll take a couple of exhaust pulses for the O2 sensor to react and the ECU to toss fuel.

 

Sounds about right, thought it was ok, but just checkin it out... Thanks bro!