Sudden loss of throttle response on the highway!

juld0zer · 06-07-2014, 09:59 AM

Is this invalid MAF reading issue unique to FI setups or can it happen to NA cars too?
I think i've experienced this sudden loss of throttle response twice now. It never happened prior to Uprev.

The only things i have done in Uprev are the fan control and 2300 throttle curve.

My revs have never gotten stuck at 4000rpm. No lights ever came on and again, no DTCs.
The best way i can describe the sensation is that the CVTC system has locked itself in high-rpm mode and the ecu doesn't realise so it doesnt set a code. The reason i describe it like this is because i put up with the opposite issue several months back. Basically, the motor felt good below 4000rpm and because most of my driving is below 4k with the occasional burst - i never realised until i started to hoof it more often.
From 4000rpm onwards, revs would take forever to climb and it felt flat. Like it had a 4000rpm rev limiter. It would eventually reach redline but it would take an eternity. I believe the CVTC system was stuck in the low-rpm mode.

On both occasions, the motor felt really lethargic below 4000rpm. So i could have my foot to the floor in 1st and the tyres would not spin. I could be in 4th following someone really close at 80kmh with my foot to the floor and not hit them - pretty much. Once it eventually reaches 4500ish rpm, the engine comes alive again but not with the same ferocity as it does normally. Which is why it leads me to think it's the CVTC.

Oil temps were no more than 92*c, coolant less than 88*c, air temp under 23*c - both times. You could also liken it to a high intake air temp lag.

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06-07-2014, 09:59 AM	#12 (permalink)
juld0zer Enthusiast Member Join Date: Nov 2012 Location: Sydney Posts: 428 Drives: 11 Nissan 370Z MB M6 Rep Power: 140	Is this invalid MAF reading issue unique to FI setups or can it happen to NA cars too? I think i've experienced this sudden loss of throttle response twice now. It never happened prior to Uprev. The only things i have done in Uprev are the fan control and 2300 throttle curve. My revs have never gotten stuck at 4000rpm. No lights ever came on and again, no DTCs. The best way i can describe the sensation is that the CVTC system has locked itself in high-rpm mode and the ecu doesn't realise so it doesnt set a code. The reason i describe it like this is because i put up with the opposite issue several months back. Basically, the motor felt good below 4000rpm and because most of my driving is below 4k with the occasional burst - i never realised until i started to hoof it more often. From 4000rpm onwards, revs would take forever to climb and it felt flat. Like it had a 4000rpm rev limiter. It would eventually reach redline but it would take an eternity. I believe the CVTC system was stuck in the low-rpm mode. On both occasions, the motor felt really lethargic below 4000rpm. So i could have my foot to the floor in 1st and the tyres would not spin. I could be in 4th following someone really close at 80kmh with my foot to the floor and not hit them - pretty much. Once it eventually reaches 4500ish rpm, the engine comes alive again but not with the same ferocity as it does normally. Which is why it leads me to think it's the CVTC. Oil temps were no more than 92c, coolant less than 88c, air temp under 23*c - both times. You could also liken it to a high intake air temp lag.