I posted this in the LT1/LT4 engine section, but I really think it is an ECM/ignition problem. Can someone take a look at this datalog below?

I need some help. Last year, I built this combination....
AI 190cc heads
11.3 to 1 CR
Custom Cam
30 LB SVO injectors
Comp R lifters
Comp 1.6 rockers
52MM TB
MSB 8.5 plug wires
Kooks headers
No cats
No Air Pump
CSR electric H20 pump
EGR is still in the intake but tube from exhaust is blocked off and it is turned off in the tune.
Tuned by CAM

It makes about 400 RWHP at 6,100.

Since we built it, I have always had a slight dip at 6,200 RPM and it has been getting worse. It now sounds like a severe ignition miss but it ALWAYS starts at exactly 6,200.

Since I have started troubleshooting this problem I have changed....
OPTI to a brand new GM unit.
New MSD coil.
Replaced 3 of the plug wires that had high resistance.
New TR55 spark plugs
Found a bad injector that was misfiring, replaced all with new 42 SVOs.
Had a little valve float from the first day we put it together and have now replaced the springs AI used with 977s and Ti retainers.
Last week we tried a different ECM and different ignition module.

None of this has helped. At exactly 6,200 RPM it misses. There are no error codes (other than ABS Inop that I have been unable to correct)

I have spent a lot of money chasing this and can not correct it. Other than this, the car runs great. It will pull smooth in 6th gear on the highway at 1,800 rpm and will also run past the miss up to the 6,700 rev limiter.


Dyno graph below.
http://img53.imageshack.us/img53/9558/picture004xq6.jpg

Datalog is here
http://www.savefile.com/files/475678

 

Have you ran a scan at that point to see what the reading are to see if something is off?

 

The scan enclosed was done on the last dyno run and should include the point where the problem occured.

 

I was thinking about a readout of the cars sensors while you drive through the drop off. There could be some unusual readout that might lead to some helpful info. I ran a scan from the mechanics shop and could see almost every thing the car was doing.

 

What equipment could I use to obtain this scan?