95 SC300, R154, Auto ECU w/ Traction control. Fender harness already relocated and intact. ECU already refurbished, FPECU not bypassed.
Earlier today I removed the hardwire jump from the neutral switch pins and installed a simple on/off switch (I reused the ECT PWR/NORM switch) and noticed while driving out of the shop that if I give it say, over half throttle under acceleration in any gear, there is random stumbles/hesitation while making my way up the rev band.
This only happens when the neutral circuit is open, with the neutral circuit closed the car behaves completely normal. I can rag on it all day and it's fine, but the moment I flip the switch and even in 4th gear trying to pass somebody it's got random stumbles. Feels kind of like when you run out of gas or when TCS kicks on. I've tested it with TCS on and off and it does it either way, the TCS light doesn't blink on the dash either.
I primarily installed the switch to get my cruise control back but also because I had read that the car changes ignition timing based on if it thinks it's in neutral or not. The only wiring I've altered is the neutral switch, the rest of the transmission range switch is untouched. The OD light flashes on the dash but that's to be expected, and the speedometer is about 10mph off because I haven't bought recalibrator yet.
Anyone seen this issue?