Help with possible ECU issue

[E_Kurtz]

I own a 95 Eclipse GST as my first car and its showing some issues i would like some help diegnosing.

Basically, whenever I start the car, for the first few minutes, it runs completely fine, good oil pressure, no shaking and an idle rpm of around 1100.

But, after a few minutes of light driving, i notice the oil pressure meter extremely low, close to zero and the car starts idleling at around 300-400rpm and strats shaking a lot.

It becomes so weak i cant even start moving without using the acceperator.

I checked all the fluid levels and they’re all fine.

My mechanic said he thinks its a problem with the ECU. (I live in Brazil and its extremely hard to find one.)

Has anyone gone across this issue before?

(the photo is not great, but shows the rpm. I am aware of the CE light, but i had just left the mechanic when i took this photo)

I would love some help.

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[dwb]

What did the mechanic say about the check engine light?
Oil pressure fluctuating is likely just cold vs hot oil and engine RPM.
A failing power transistor causes symptoms similar as you described.

 

[E_Kurtz]

What did the mechanic say about the check engine light?
Oil pressure fluctuating is likely just cold vs hot oil and engine RPM.
A failing power transistor causes symptoms similar as you described.

Hey, thanks for the reply!

He said he thinks its caused by the ECU, the light turns on and off randomly.

Is it still healthy for the oil meter to be close to 0 while driving? I tought it could be caused by the engine beign too weak to properly move the oil around.

Do you know if its an easy fix to change the power transistor?

 

[dwb]

Your mechanic should have pulled the code. I would question why they did not if this symptom is why you brought it in.
Check your grounding points if the ECU is losing power. That's not causing it to run on two cylinders, though.
The stock oil pressure gauge is not the most accurate. If you're concerned about oil pressure, an aftermarket gauge would be the best way to verify. You can also open the oil cap while it's running and see oil flinging around off the cams and out the oil cap hole (watch out for the mess). Take a look at my posts here that shows an aftermarket gauge (tapped into the head, so not same pressure as at the OFH) vs stock 1g gauge both hot and cold: https://www.dsmtuners.com/threads/r...ttle-low-load-open-loop.543706/post-153891302. A few posts down I have examples of how the oil looks under the cap.
Yes, the PT is simple to replace. Do some research on it, don't just take my word for it.

 

[E_Kurtz]

I´m going to ask him about the codes, the car spent around 9-10 month at the shop (its really hard to find parts here).

Thanks for the tip on the oil cap, im going to try it and post it here.

About the PT, im going to look into it and talk to my mechanic, but do you know of any other simmilar issues that cause the rpm to randomly become really low when the engine is hot? Thanks.

 

[dwb]

Maybe the ignition coil. Not as common as PT, though.