I got a 94 SC400. Lately it's been having issues with starting, when I leave the car overnight and start it in the morning it starts right up. I'll drive it to work and leave it for 8 hours then go to start it up and it cranks for 2-3 seconds before starting. SOmetimes it drives like an absolute beauty, but sometimes the acceleration is so laggy and Jerky. Sometimes it shifts super smooth for the whole ride but the next drive it shifts rough. Occasionally the exhaust will give off bad fumes. At this point I feel like if it was the fuel pump
or Injectors these issues would be consistent not one day it drives great and another it drives like ****. I also can't tell if it's the starter or not, I got it tested at O'Reilly and it tested good, I would assumes if it was the starter it would have a hard time starting EVERY time not only after its been driven. I'm thinking it's something electrical
Here is what I've done so far
Rebuilt ECU
spark plugs
coil wires
ignition coils
compression test
vacuum leak test
Bypassed charcoal fuel canister

Here is what I'm thinking could be wrong
bad MAF sensor
Clogged cats
Bad wiring harness
Bad fuses
Maybe bad fuel ECU

Any help is GREATLY appreciated

 

Any stored codes?

Did the behavior change after the rebuilt ECU? (Did you get yours serviced, or was it a new one to the vehicle?)

 

yes sorry I forgot to mention that, CEL is on but won't read codes, I had the ECU serviced. Behavior was much better after ECU rebuild, but the lagging acceleration and rough shifting issue still remained but it got better after the rebuild. The starting issue only appeared after the rebuild

 

Won't read codes or doesn't display codes?

I would start by trying to find someone local with a good working ECU that you could borrow, before chasing your tail with other stuff. It sounds like general ECU problems, so I'm thinking the rebuild didn't fully fix the issue.

The semi-warm start issue is likely unrelated if it started after the rebuild.

 

It won't read codes, codes are showing up but when I jump the ports nothing happens. But I think you may be right about the ECU not being fully fixed. I unfortunately do not know anyone with an sc400, I might purchase one from ebay from a verified seller and see what happens from there. Would you happen to know anything about that starting issue though?
Thank you for the help

 

It's been too long to remember all the warm start stuff, but I sort of recall cleaning the IACV helped with that.

Definitely sounds like your ECU is still problematic.

 

First bypass the fuel pump ECU ifthat doesnt work i have a 1994 SC400 ECU that was rebuilt and works that i will sell you if interested