Hi knowledgeable car folks
I know my question is not about tuning per se, but I really need some help here. These last couple of years my freshly built 1991 Nissan 300ZX/LS3 (see specs below) has developed a nasty, and potentially very dangerous habit of going into limp mode unexpectedly.

The code is always the same: P2135. It used to be quite intermittent, like going several hundred miles, then failing two or three times in a row. Now it’s happening much more often (except of course if I have tech in the car with me!)

I’ve gotten a lot of support locally, and the folks at PSI are great, but still we’ve been unable to find the actual cause of the problem so we can fix it. I bought a $500 Autel scanner and do have some live data, and enhanced freeze data after a failure, but still no smoking gun.

I love this car; it’s beautiful and big fun to drive, but I’m afraid to drive it much for fear of being rear-ended or causing an accident behind me.

I really need a solid course of action here. Can you help?

Thanks, Mo

What we have done so far:

· Replaced aftermarket TB with OEM

· Replaced gas pedal with OEM

· Replaced PCM (The car likes this new PSI one a LOT. Runs smoother, quieter, doesn’t stall off load like it did before. The first one was not done by PSI)

· Went through the throttle actuation wiring and found it to be in-spec.



Specs:
Engine & Related:

· Brand new GMPP Crate LS3

· 6.2 Liter

· Factory GMPP hot cam (480HP)

· OEM gold plate throttle body

· OEM gas pedal

· Aftermarket Sheet metal intake

· K&N C6 Corvette cold air kit and filter

PCM:

· E38 Programmed for my car by Performance Systems Integration (PSI) (Have spec sheet)

· 2008 Corvette

Wiring Harness:

· Custom built for this application by PSI