Modified plenium, Z1 Test pipes, Motordyne Catback

Vincenzo

Many thanks for the reply, I have most of the mods complete with the exception of the motordyne exhaust. (back-ordered) I installed the test pipes had it tuned by Z! using the mail-in service.

This weekend, I just swapped my plenum upper manifold with a new ported one, and after

Now after I installed the new manifold and reset the ECU when in the high-performance mode it does great until I hit 60mph and then it acts like it is in valet mode and sometimes RPMS drops dramatically or it just cruises along with no acceleration and that process repeats itself. When I put it in stock mode I can feel the gains and it runs fine. I'm going to get another tune after the exhaust is installed but I don't want to wait if it's a mechanical issue. Anyone have this problem before? If so, how did you fix it? Could it be a tuning issue? Thanks in advance and have a good one!