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Cebal · 01-28-2021, 07:51 AM

Hi. Got pretty annoying problem to deal with. Searched internet/google for a fix but nothing helped.

First of all I have a manual transmition, boosted BRZ with FBM turbo kit. The problem is that when im driving, comming to a stop sign I put it in neutral gear and my car's RPM goes really low like 400-500 RPM, feels like car is almost stalling. It stalls once for a while cause of that and im trying to find a solution. I think it's getting worse when the car is getting hot. No CEL at all. Battery is weak but the car starts fine every time without a problem. It feels like car runs just fine when on gear, it pulls etc. When I rev it to the limit and hold it for a sec or 2 it sounds like it backfire's. Could faulty o2 sensor cause misfires on all cylinders? I ran out of ideas to be honest and im looking for your help. I checked logs using EcuTek connect app and there was multiple cylinder misfires. AFR on idle is between 12-16.

List what I changed/checked already to fix it:
- changed spark plugs, new HKS M50-HL plugs
- changed coil packs, new Delicious Tuning OEM+ coils
- changed injectors, new ID 1050X (remotely tuned them)
- changed MAF, new OEM one
- changed Coolant temp sensor, new one
- changed throttle body and throttle body sensor
- clamped evap lines under the intake
- checked for vacuum leaks, all good
- installed boost gauge, its building boost just fine, 10 psi like it should
- all 3 bolts on injectors module are solid

I made a short log how it's running on idle and I captured the moment it's RPM hunting and dipping especially at the end of the log. It does it on idle after I press on acceleration pedal and RPMs go down. I dont know what my fuel pressure should be so im not sure if it's right. I assume fuel pump is fine since my car starts fine every time.
Look at the log, there's multiple misfire, wild AFR, RPM dip etc.

https://datazap.me/u/cebal/log-16118...og=0&data=3-19

Thanks in advance

01-28-2021, 07:51 AM	#1
Cebal Member Join Date: May 2018 Drives: 15' BRZ Limited Location: Europe Posts: 23 Thanks: 5 Thanked 14 Times in 7 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	RPM dip, stalling on idle Hi. Got pretty annoying problem to deal with. Searched internet/google for a fix but nothing helped. First of all I have a manual transmition, boosted BRZ with FBM turbo kit. The problem is that when im driving, comming to a stop sign I put it in neutral gear and my car's RPM goes really low like 400-500 RPM, feels like car is almost stalling. It stalls once for a while cause of that and im trying to find a solution. I think it's getting worse when the car is getting hot. No CEL at all. Battery is weak but the car starts fine every time without a problem. It feels like car runs just fine when on gear, it pulls etc. When I rev it to the limit and hold it for a sec or 2 it sounds like it backfire's. Could faulty o2 sensor cause misfires on all cylinders? I ran out of ideas to be honest and im looking for your help. I checked logs using EcuTek connect app and there was multiple cylinder misfires. AFR on idle is between 12-16. List what I changed/checked already to fix it: - changed spark plugs, new HKS M50-HL plugs - changed coil packs, new Delicious Tuning OEM+ coils - changed injectors, new ID 1050X (remotely tuned them) - changed MAF, new OEM one - changed Coolant temp sensor, new one - changed throttle body and throttle body sensor - clamped evap lines under the intake - checked for vacuum leaks, all good - installed boost gauge, its building boost just fine, 10 psi like it should - all 3 bolts on injectors module are solid I made a short log how it's running on idle and I captured the moment it's RPM hunting and dipping especially at the end of the log. It does it on idle after I press on acceleration pedal and RPMs go down. I dont know what my fuel pressure should be so im not sure if it's right. I assume fuel pump is fine since my car starts fine every time. Look at the log, there's multiple misfire, wild AFR, RPM dip etc. https://datazap.me/u/cebal/log-16118...og=0&data=3-19 Thanks in advance Last edited by Cebal; 01-28-2021 at 08:54 AM.