i had a similar problem after the install of an aftermarket CAI. I had changed the position of the MAF not realizing it. Someone hinted to me to position it back to 10-12 o'clock. Never had a problem again. May not be your issue, but check to see if the MAF is positioned where it was orginally....
Bo
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2008 Shelby GT500 Black Coupe
JLT CAI, MRT H-pipe, FRPP Axle back
BMR UCA,LCA's and Panhard bar (Adujustable)
532rwhp/572rwtq
2003 SVT Cobra Coupe.....SOLD
#154 of 8694