nismofreak1208

Hi all.

I repaired my intake manifold changeover valve system by replacing the broken plastic arms with gruvenparts metal 1" arms. When I started the car, there was strong vibration at idle which went away after a battery reset but I get a surge when driving. When driving at speed, example 60mph, as soon as I let off the gas pedal, the rpm needle drops about 300 rpm then goes back up and once I touch the gas pedal again, it's like a rough vibration as it feels like the transmission is catching back up with the engine speed or vice versa. This strange surge and random rough transmission engagements is strange to me. On full hard launch, I get a lag around 6500-6800 as if its a momentary pause or disconnect in power (unless it is when the valves fully open under WOT). I was hoping someone could help point me in the direction of what's wrong.

On a side note, the car feels extra peppy and accelerates harder now.

I'll attempt to take some good video recordings, I tried early this evening but it was a bit blurry

mishar

That sounds more like transmission, but some of it may come from those changeover flaps. Are they free to rotate?

nismofreak1208

Yes, I rotated by hand and there was no issue. There was also no issue afterwards with startup or shutdown with the flaps as they both seemed to have smooth operation

MP4.2+6.0

Does sound like tranny. Check tranny fluid level as a logical next step.