Ive read a ton before deciding to upgrade my trucks OS to 1 bar SD using my hp tuner. Much Easier to tune. One question, ive read when disable the maf by changing codes P0101, P0102, P0103 to use function 2 (no MIL light) because your vehicle still needs to use the AIT but not the MAF. Ive also read change the codes to 3 (no error reported) because if there set on 2 it will alter the way it shifts. I have noticed if i have them set to 2 it shifts from park to gear much harder then it does in 3. But set in 3 the idle seems to surge up and down. Anyone know or have any experience with what im explaining with advice would be great. Thanks.

 

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In some of the early 411 pcms, failing the maf would put the trans in a 'full line pressure' mode. There is another code to change to keep this from happening when failing the maf to force it into speed density. Why are my shifts so hard while in Speed Density? - HP Tuners Bulletin Board The maf codes need to be set to 'no mil light', if no error is reported the pcm will not default into speed density mode.