popcorn sound

[GP99GT]

i know this isnt the right place for ford tech, but hey why not. maybe someones got an idea

under WOT acceleration, from 4800rpm on, the car kinda pops through the exhaust a bunch of times and i feel a drop in power. It did this before the intake was installed, so i checked the timing and advanced it to 15 degrees base, and all was well. made lots of track passes on it, no problem. ever since the intake was put on, the problem is back. i set timing at 18* and it didnt do it as much (seemingly anyway.) no codes on the scanner. car also has no AIR system, no EGR (disabled the right way).

i got a video so you can hear it and see when it happens. starts doing it at 4700ish RPM(13sec), more noticeable at 5000+. helps if you turn down the bass if you have a subwoofer. http://www.youtube.com/watch?v=ojVNLh3Pcho

also i noticed on the A/F chart for my dyno run, it was lean (14:1) til about 4800rpm, then it dumped in fuel and went down to around 13:1. could that have anything to do with it? heres a link to a scan of the sheet.
http://img101.imageshack.us/img101/457/dynosheetol1.jpg

[foff667]

audible knock possibly.

[GP99GT]

if its knock wouldnt it do it all the time? once in a while i get a WOT run when it wont do it at all. someone on another site suggested the coil is going bad and cant supply enough voltage in the upper RPMs because its firing so fast. maybe time to switch to an MSD 6AL box

[V]

i have a 6A for sale w/coil
(the 6AL just has a rev limiter and rubber mounts)

[GP99GT]

well i kinda want a rev limiter for powershifting

what do you want for it

[GP99GT]

i grabbed some spark plug wire seperators and went at it. took it for a short drive, no pinging...mustve been a crossfiring wire or something. im gonna keep my ears open though