I've just had an issue with my 99 2.5RS (EJ207 swap with VF28) having a major power loss under hard acceleration around 4k-5k RPM. So far this has happened in 3rd, 4th, and 5th gear. It feels like a fuel cutoff and causes an immense jerking. The only thing that changed today is that I filled up with 94 octane while normally the car is filled with 92. Would this by chance have anything to do with the cutoff? I'm not terribly technical (I am however, technically terrible) so perhaps the experts here might know what some causes of this might be?
Also probably important is that the car was tuned with a different catless DP and catback before I switched it to an 05 OEM STI turboback to pass emissions. This however was done quite a while ago and has never given me any issue until potentially today. Actually what is probably related is that previously, under hard acceleration at similar RPMS (perhaps slightly higher) there was a rattling sound being emitted from the engine bay. I tried to get it to happen again today but it no longer was happening although now I am having this power loss issue.
Thanks
EJ207
JDM ECU
VF28 Turbo
05 USDM STI Turboback
Also probably important is that the car was tuned with a different catless DP and catback before I switched it to an 05 OEM STI turboback to pass emissions. This however was done quite a while ago and has never given me any issue until potentially today. Actually what is probably related is that previously, under hard acceleration at similar RPMS (perhaps slightly higher) there was a rattling sound being emitted from the engine bay. I tried to get it to happen again today but it no longer was happening although now I am having this power loss issue.
Thanks
EJ207
JDM ECU
VF28 Turbo
05 USDM STI Turboback
