[Lulmago]

Okay guys so I reallly need help
07 Honda Civic si sedan k20z3
Completely stock other then k&n SRI
Car has been idling real rough but never turned off until recently
Long story short I got the car from a used dealership and the motor blew next day
So they replaced it w a 140k new one
And told me all it needed was a knock sensor so I installed it and It didn’t change anything at all
I got a job that works long hours so I’ve been just driving it like that
But recently it started to turn off on me while driving
If in gear and go into neautral it’ll idle from 200-1k rpm then just shut off
Showing battery and oil lights
I do have a check engine light for bank 1 sensor 1 o2 , knock sensor and a coolant temp sensor
I replaced knock sensor and o2 sensor w oem parts and nothing . Light doesn’t go away either
Funny thing is if I unplug the MAF sensor it’ll idle perfect and all but go into a limp mode where I can’t pass 3k rpm (68mph)
But if I plug it back in , it idles like ****
So I swapped the maf w a new one oem ofc and even did sparks for the hell of it and nothing changed at all
I just got a/c recharged , wasn’t working before and now it causes my car to idle even more rough when the a/c is running
I have no idea what it could be
MAP maybe ? Throttle body ??
I sprayed the tb w tb cleaner and cleaned her up a bit but nothing
It seems to be getting worse
Please help !!!

 

[Diignity]

Did you replace coolant temp sensor?

 

[Lulmago]

Did you replace coolant temp sensor?

No I haven’t replaced it yet , car doesn’t over heat or show any signs of leakage or anything
I doubt that’s what’s making the car idle like **** ?

 

[Diignity]

No I haven’t replaced it yet , car doesn’t over heat or show any signs of leakage or anything
I doubt that’s what’s making the car idle like **** ?

A faulty coolant temp sensor can definitely make your car idle poorly.

 

[Lulmago]

A faulty coolant temp sensor can definitely make your car idle poorly.

I’ll change it out today , but I barely changed the maf yesterday , before I swapped it it’ll still drive w it being plugged in but would still idle really rough , now with the new maf if I plug it in and start the car it’ll idle normal for about 2 seconds then completely idle like **** for 2-3 seconds and die out , I try to rev it up but I don’t get throttle response , or if I do it’s really really sluggish like it’s retarding

 

[Diignity]

I’ll change it out today , but I barely changed the maf yesterday , before I swapped it it’ll still drive w it being plugged in but would still idle really rough , now with the new maf if I plug it in and start the car it’ll idle normal for about 2 seconds then completely idle like **** for 2-3 seconds and die out , I try to rev it up but I don’t get throttle response , or if I do it’s really really sluggish like it’s retarding

I'm not sure if problem is still occurring after Coolant Temp Sensor replacement but I forgot to ask is there any codes being thrown?

 

[RabbitsFoot]

Sorry for the late reply, I just saw this thread.

You mentioned that you cleaned the throttle body. When you did this, did you push the throttle plate at all, or did you just spray cleaner and wipe around it? If you did move the throttle plate at all while cleaning, you will have to do a throttle body position calibration. This happened to me the first time I cleaned the throttle body on my FA5, and it took me quite a while to figure it out... there are guides on how to do this, but TL;DR you need a diagnostic tool with the calibration procedure on it.