1G Warm start issues, unstable idle, stalling

[kirai]

I have a 1992 Mitsubishi Eclipse GS 150 HP. When the engine is cold, the car starts without any problem, but when the engine is warm, it takes about 5 seconds to start. Other things I noticed were recently, after driving about 15 kilometers (15-25 minutes of driving), the RPMs started to change rapidly (they started to suddenly drop and then increase slightly, they were very unstable) until the car completely stalled while driving. Then I had to start it for about 10 seconds and while driving, the engine kept turning off. Finally, after one car engine stalled, I couldn't start it anymore and had to come back for it after a few hours until it was cold, then it started and drove without any problems.

I will also add that until the first changes in RPM's, the car runs without any problems and there is no sign of anything going wrong. Changes in RPM start to happen suddenly after a longer time of driving (maybe about 30 minutes but it not always happening in the same time)

 

[dsm_jeb]

Have you tried swapping a known good coil pack in?

 

[kirai]

Have you tried swapping a known good coil pack in?

No, I didn't change the coils. Is it possible that this is the reason for my problem. If the coils were damaged, wouldn't there be also a problem with starting the engine when it's cold?
Can I somehow check myself whether the coils are working properly? I also think about fuel pressure regulator, but I don't really know.

 

[turbomister2]

Just diagnosed my brothers car that did this same thing, would start perfect cold but warm was a nightmare
One of his injectors was leaking down after the car shut off so pretty much was “flooding” a cylinder

 

[kirai]

Just diagnosed my brothers car that did this same thing, would start perfect cold but warm was a nightmare
One of his injectors was leaking down after the car shut off so pretty much was “flooding” a cylinder

Oh, that might be it. I hadn't even thought about it. Do you know how I can check if the injector is leaking? Your brother just bought new fuel injectors to fix it?

 

[turbomister2]

So he had a plug that was black where all the others were perfect
We swapped coils just so we could eliminate them being an issue and it stayed “problematic” on same cylinder
Than marked the injector and swapped it and same thing on a different cylinder
You can find someone local to test, clean and repair them possibly

 

[kirai]

So he had a plug that was black where all the others were perfect
We swapped coils just so we could eliminate them being an issue and it stayed “problematic” on same cylinder
Than marked the injector and swapped it and same thing on a different cylinder
You can find someone local to test, clean and repair them possibly

Okay, thank you so much. I really appreciate it.

 

[turbomister2]

Okay, thank you so much. I really appreciate it.

No problem
Hope it helps out

 

[dwb]

Have you checked for any fault codes (check engine light)? It might also be beneficial to open up the ECU and check for capacitor leakage/PCB damage (take some pictures and post them up here).

Idle surge is what it sounds like the other issue you are describing. It is often caused by a vacuum leak, failing sensor (MAF, ISC, TPS, IPS), a failed FIAV, or leaking ECU capacitors.

 

[kirai]

Have you checked for any fault codes (check engine light)? It might also be beneficial to open up the ECU and check for capacitor leakage/PCB damage (take some pictures and post them up here).

Idle surge is what it sounds like the other issue you are describing. It is often caused by a vacuum leak, failing sensor (MAF, ISC, TPS, IPS), a failed FIAV, or leaking ECU capacitors.

No check engine light appears or anything like that. Unfortunately I've been short on time lately, but I'll try to find time to find and open the ECU