If you're positive everything is right, see my post below a few posts down about the dielectric grease on PTU and CAS connections...I just did headgaskets on my TT and when I put it back together only 2 cylinders would fire even though i cleaned everything. Got some dielectric grease and ran perfect...in fact, first try to turn over engine after timing belt install etc, it wasn't firing on any cylinders due to PTU...it didn't even look dirty