I have this on the aftermarket site but I need help now. I put my Airforce One on this morning and my 5.4 wouldn't idle and had a nasty whining sound like a screamin elk. I put the old stuff back on and it ran like a champ so didn't ruin any sensors. Can't figure out why my install wouldn't work. I admit I don't know squat about mechanics but thought this was a no brainer install for dorks like me. Good thing I had my new Magnaflow ct installed by the shop. Any ideas?

 

Sounds like a vacuum leak. Make sure that all of the connections are very tight; including those areas where sensors are mounted on the intake tube.

You may also want to reset the computer so it will adjust for the increased air flow more quickly.

 

Found it. I had the tube too far in the connector near the throat and it was blocking both breather tubes. Runs great now. Thanks.