Hi,

Glad to hear that you haven’t looked into that gadget behind the battery yet.
It’s an inconspicuous item, flopped right in the middle of the ignition system.
It looks so simple and small but isn’t everything in the other two electronic items that you have tested.

As far as exchanging the ECUs again, I don’t know what you will gain unless you have never done a hard reset to the one in the car now.
A hard reset is leaving the whole EZK system disconnected from the battery for a real long time.
His ECU has been disconnected so who knows?

In my recent circle chase, it was like almost a week before I was got back to putting the battery back on.
The last things I messed with was exchanging the spark coil relay component and hooking the battery back up. The 30 second running and dying thing totally stopped.
Doing one thing and then testing for a result of change is the only way I think.

I’m stumped as well on last component that you are about to TEST … check out?
I believe you are definitely slowing down, due to a shortage of things to test, so restraint is on its way.😎

I have only read the following in industrial magazines about shielding from electrical noise from the air and other ways signals travel through power supplies lines.
The electric smart meters on your home use the very power lines as a communication circuit.
So many ways a person can be wired and it’s the future of speed within technologies.

A hard reset is supposedly done quicker by putting the two the battery cable leads together so everything in all the circuits everywhere, discharge to zero or a virgin status.
Like in no static charge held on surfaces or inside these highly sophisticated chips used today.

I suggest clamping them for several minutes to give things a rest and deplete out.
Nothing to lose except time and you can do other things in the meantime.
A good cleaning and inspection can always be justified on batteries.

A Couple other things that have popped in my mind.
One is to ask if this car has an EGR valve?
If it opens at the wrong time or hangs open the engine will run rough.
Hot Exhaust gases lean out or dilute the mixture.

I have had to clean the controlling valve to it twice on my 1991.
The valve is Located on the left fender. It can get a clogged port below the tiny cap. It doesn’t vent properly.

It trips the CEL, if the ECU doesn’t see a temperature change from the sensor inside the EGR valve itself.
Apply vacuum to the valve directly to see if the steel stem moves back and forth with its diaphragm.

Second thought is the valve on top of the fuel vapor canister.
The canister is mounted below the left side front bumper.
The valve is only supposed to open during idle or during high vacuum times.
It function is to pull air and gas vapors from the fuel tank.

If the smaller hose going to it from the manifold or the larger hose from the valve to both ports above the throttle plate body.
If the valve gets plugged up and doesn’t close off then it’s sucking air from the fuel tank all the time.
A rotted or split hose IS an air leak. I have found such a bad hose rotten just out of sight under the frame to the canister.
These ports have “sized” nipples so don’t get them or the hoses reversed, if that’s possible?
The throttle plate is centered underneath these port holes.
Another reason for a proper adjusted, cleaned and sealed throttle body to the manifold.

There are four cylinders as it’s not the one intermittent misfire that you started out with.
A bad spark plug or the wrong gaps cause this most of the time and then it gets worse.
There has to be an explanation for this rather repetitive roughness.


Phil