Just finished a 4" from MAF to TB intake setup on the truck. Did this to cure boost leak and popping the stock intake.

One problem--now my part throttle 1-2 and 2-3 shifts are slipping. slipping so bad I have to let off to get it to catch the next gear. They used to be super hard and quick.

I tried some 3/4 throttle, and they still barked the tires, so I dont think its my trans going out.

The only thing I did that I can think of that might cause it is, while pressure testing my intake tubing I found 1 leak--3 holes around the outside of the MAF. Dont know what they are for. Looking back this probably wasn't a good idea, but I dabbed some silicone into the holes to seal them up.

Ive heard MAF calibration can change line pressure. Could this have done it?

 

well, going out to dig the silicone out now.

 

Yep. The MAF has a lot to do with the line pressure.

 

you think a vaccum modulated upgrade would fix this? i know they use them on the flp trannys. www.pro-built.net sells the kit to do this and it comes with a box to plug into the harness to keep the computer happy. just a thought

 

You have any pictures of your intake setup?
BTW mine slips at WOT from 1-2. I think the band is slipping. Does not do it unless WOT