Help: Altis 1.6 RPM Drops to 400

[itsme_waqas]

Hi Fellow Members,

I have an Altis 1.6 SR Cruisetronic 165K driven, I am the first owner and the car is maintained from Toyota Dealership in Lahore. I recently got the Tuning, Spark Plugs changed, Throttle Body cleaning done (Appx 100kms driven after that). Today while driving I was crossing a speed breaker at a speed of 10km/h and the check light turned on for the first time since I've had this car and CHECK ENGINE SYSTEM in the meter. The RPM dropped to 300-400 and the engine started shaking terribly. I immediately parked it and turned the engine off. After a few mins tried to start it, it started totally fine but the check light was still there and as I put it in D it started the same vibration and RPM dropped to 300-400.

I started driving and the car got a little better in terms of vibration. After I slowed down the same behavior. So in short at slow speed the vibration is intense and as I speed up it gets better.

I have parked it at my home and will take it to Toyota tomorrow morning. Can anyone please help me what might be the issue?

Thank you

[zakiuddin]

It needs proper diagnosis but if i have to pick something with usual symptoms, i'd say you lost a coil in one of the cylinders.

[ahmedstudio]

I believe it's bad idle control valve. Get it scanned for OBD error code and share.

[itsme_waqas]

You were right, it was the coil. Got it replaced and everything is working fine now

[itsme_waqas]

But the interesting thing is when I reached Toyota the scanner said it is only 1 coil in D cylinder.

And while they were checking 2 more went away, so I had to get 3 of them. Now I am worried if I am going to be in this loop, losing coils unexpectedly anytime. Is there any solution to it? I had the wiring plugs etc everything checked. All good.

Thanks for the help.

[zakiuddin]

Lifespan of an ignition coil is around 100,000 miles or 160,000kms. So its not surprising that they are failing now.
Replace the 4th one to be safe and keep it as a spare...