Strange miss at high rpm...(long)

[BLACK MAGIC RACING]

THis all started last week, the car was running strong, with passes in the 10.60-10.80 range. all of the sudden, on my 4th pass of the day, the car won't rev past around 55-5800 rpm,it's kind of missing, like it's hitting a rev limiter or something. run ended in a 11.20. i get back to the pit, and checked all my grounds, as it seemed like a ground issue. i noticed that the nuts holding the coil/module assembly are loose, so i tighten them up, hoping the prob is solved, not so. after nothing changed on the next pass, i figured maybe my msd dis-4 ho was messing up, so i unplugged it and put the jumper in. same thing. i decide to go home. i start checking things out. i ohm my plug wires, and get numbers all over the place, so i put some new taylor 409's on, and figure since my module is the original one from the factory, maybe that's part of it, so a new one goes on. i get to the track today, so sure that i solved my problem, but no such luck, the miss is still there. all intercooler hose clamps are tight, all grounds are good, coil pack, module, plugs and wires are all new,numbers were normal all the way down the track (02's in the 770-790 range, boost stayed steady at 20 lbs, etc..) wtf is going on????

 

[onefastgn]

Same problem hear,Ive had too retard the timing to stop the missing at high RPM with my translator plus.Give me your phone number and maybe between the two of us we can help each other.

 

[BLACK MAGIC RACING]

Big stu brought up a good point in the other thread i posted, maybe valve springs. now that he mentioned it, it does sound a lot like valve float, i'm going to check my rocker adjustment tomorrow.

 

[onefastgn]

Did you find out anything yet?Just checking

 

[BLACK MAGIC RACING]

I re-adjusted all the valves, and no effect. i did, however, notice a big improvement when i turned the MAF WOT switch back to 0, that's where it was when i ran the 10.64, but my 02's were low, so i turned it up at the track last week. back to zero seems pretty good, so i'm gonna try it this weekend and let u know how it goes. what's your maf setting?

 

[onefastgn]

I have mine set @ 2 for 10% lean @Idle and 3 for 6% MAF @WOT and 0 for no change and 7 for up to 7.5 degrees retard at 6400 rpm and have used the number 6 setting instead of the 7 setting and had about the same luck.I have also tried all the same things that you have tried too I just unhooked my MSD Dis 4 all together because I was told that it might be some of the problem because it is 6 or 7 years old.Ive even rechecked the timming and it made no difference,The last time I ran it I could only get 11.4 in the 1/4 when it used to run 10.85 with no problems.I will pm you my phone number so that maybe we can talk more about this if you would like.