CEL p1120

[PlumCrazy]

I keep getting a p1120 Manufacturer air fuel metering. It only comes on at start up. If I delete it I can drive for hours with no problem, but then I if I shut it off and restart it the light comes back. It seems to run a little rough for a few seconds before it trips the light, but then it clears up. Also seems to have a high idle sometimes (like 2000).

I have already replaced the MAF, Idle air control, and TP sensor. I am thinking maybe one of the injectors leaks off while the truck is off then when I go to start it, then it trips the code because the air/fuel mix is off. Or I am thinking O2 sensors.

Let me know what you guys think.

-plumcrazy

 

[tdog]

p1120 has to do with the TP sensor "closed " voltage. Not saying it is the T
P sensor but it would be a good place to start.>>>>I have seen bent throttle shfts give the same code.

 

[PlumCrazy]

TP sensor is brand new. I took the throttle body off and cleaned it/inspected it for any damage and it didnt change anything, the throttle opens and closes smoothly there are no rough spots or anything, it closes all the way and opens all the way. Everywhere I have read says TP sensor, but my scanner says air/fuel metering. I checked the fuel pressure today and it is lower than it should be. haynes says it should be 30 - 45 at idle, mine is like 28. I already replaced the filter, so now I am thinking pump or regulator.

-plumcrazy