Weird Issue with idle?

SCEnthuzy

Registered User
Heya guys hows it goin?

I normally do not post much on here, but I am becoming very invested in my car and everyone seems to be nice and helpful on here, I thank you for that! Anyway here goes, so throughout the 5 or so months I have owned my SC she has been good but she has her episodes. I have replaced the cam sensor, crank sensor, and DIS. Mind you I am the third owner and she has 110,xxx miles. Anyway sometimes (and its completely random) I will go to start it and it starts but sounds like its running on 3 or so cylinders and shakes like crazy it sounds terrible and when it dies it makes this sorta wind tunnel noise like liquid is draining,, it will do this until it dies. When it does this just after start up I can rev it to about 3 grand and it will come back down and idle just fine. It is weird because I have discovered that if I unplug the coolant temp sensor, it will not do this at all it will start every time no problems! It actually seems to run better without the coolant sensor, and the fan seems to not want to turn on with the coolant sensor plugged in anyway. So I have been driving it with the coolant sensor unplugged, hopefully that's not damaging but as far as I know the fan on 24/7 means it will stay cool which is reassuring to me. I look forward to discussing this

Thanks,

Zach
 
The reason it runs differently with the coolant temperature sensor unplugged is because the computer goes into a different mode. Limp mode specifically. It turns the fan on and runs a different program. When all of the sensors are plugged in, functional and your car is up to operating temperature, it is in closed loop. This means the PCM is adaptively operating and controlling your engine. If your engine is running rough, then stalling in closed loop then I believe you have a vacuum leak. I would Reseal the IC tubes as they are the typical offenders however if the problem still persists you will need to have a smoke test performed to determine where the vacuum leak is located.
 
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