Replaced APPS - Threw Codes Again

[WAdams]

I replaced the APPS (Under the battery box) on my 03 and had the codes reset. 1 day later the codes are back and so is the intermittent dead pedal and bucking. What to do now??

 

[JLandry]

What are the codes?



How many miles on the truck?



Did the symptoms start suddenly or come on gradually?



How long has this been happening?



What other work has been done on the truck?



Thanks,



John L.

 

[WAdams]

2003 HO, 6-speed, 204k. Stock. Started in Aug. Very intermittent. Problems with very brief dead pedal and slight buck weeks before the check engine light came on. 1st code was P2121. A few weeks later another check engine light with P2122. Still very intermittent. 1 hour drive to work, some days no issues. Replaced the APPS, had the codes reset. One day later the codes are back, dead pedal and bucking. Just before the bucking started again, the truck would not respond to hard acceleration. Gradual increase in speed was okay. Changed the fuel filter and the inline filter that came with the recently replaced lift pump. That problem went away. 1 hour later the check engine light.