Ok about a month ago i ripped my heaton of ande tossed on a brand new MP sc. sinc then i keep throwing two codes. p171 p174 i know what these two codes mean and Ive down everything to try and find the leak i bought all new gasket for the TB and plenum i even sealed the Sc with a little bit of extra sealer. I've checked all the hoses and none are missing or cracked. I checked my air fuel ratio and with the truck idling and cruising normally im right aroun 14.4 and when i jump on it she sits around 11.7 and holds steady till i lift of and cruise to a stop when it jumps really high to like 20.0. But i dont hear any backfiring jsut to let you know. and if i put my foot back into it it goes right back to where it should be. I replaced alot of the little vacuum lines thinking maybe a tiny hole or crack and still nothing. Everytime i replace something i clear the code and drive and 35- 40 miles down the road the codes come back. I'm totally lost and have no clue where to go now. And i cant afford to toss her into an expensive shop up here where itll cost me a couple grand to fix something minor. any ideas guys.
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