First things first, this is my first post here so I apologize if this has been asked before.

I recently bought an 1997 SC400 with 250k miles. The previous owner changed the IACV, throttle position sensor, spark plugs and wires, distributor caps and rotors, ignition coils, fuel injectors, and removed a clogged cat.
The problem I have is that the car has a rough idle when parked. It also struggles and jerks when accelerating from 0 and also when going in reverse, I also get a strong smell of gas. I checked for codes and first I got a P0172 saying that I'm running rich, last night that code went away but now I have a code for misfire on cylinder 1, one last thing is that when driving 40+ mph and I let go the gas quick, I feel like the car jerks for a second.

I had someone inspect the car and I was told that the injector in cylinder one was not replaced and I contacted previous owner and he did in fact said that when he replaced it, it was leaking so he put the old injector back. While doing some research I found out that the ECU could be the reason for these problems as well so I'm currently waiting for new injectors and I'm not sure if my ECU is bad or not. I will attach a picture of the ECU, it seemed fine except for a little brown spot close to some capacitors.

 

Welcome to the site,
Well, it's leaking, since the car is down contact Tanin electonix, you could probably find a link somewhere on this site. Email them about addressing your ECU. They no longer have a link so you have to contact them for a work order number. Ship your ECU to them and it will probably fix most of your issues. If some persist then it may be another issue, but atleast you will be able to figure it out from there.