Car is a 2000 civic si with a JDM type r b18c. ECU is a p28 chipped with hondata v3. Also has the hondata coilpack retrofit. When the car is cold it will stumble at about 3k rpm and sputter with continuous throttle until it gets warmed up and then it's fine for the most part with the occasional stumble here and there. Any idea what it may be?

 

CEL codes?

Last full ignition system tune up?

 

Last tune up was a month ago before I purchased the car. And no CEL codes whatsoever. The light does work

 

Details? What was done?

 

Spark plugs, fuel filter, new belts, oil changed, coolant drained and replaced!

 

I was thinking it could be the tune due to the previous owner having it tuned by a friend rather than having it tuned professionally at a reputable tuning company

 

I don't see ignition timing on your list, though this may be part of the "tune" you mentioned.

 

But would timing be a problem only when the motor runs cold and is fixed when it warms up?

 

What the base ignition timing setting? Do you know?

 

Absolutely no clue! Haha since it has the coilpack retrofit does that remove the possibility of it being distributor related?

 

How was the retrofit done? Is a distributor with its sensors still installed?

 

It's basically a distributor without the cap

It's this: https://www.hondata.com/coil-pack-retrofit

Nobody?

 

Indicates that distributor could be the problem. However, here's where your main focus should be:

You appear to have purchased/inherited the previous owner's problem.

 

I know tuning can be expensive to have it done professionally so I just wanted to see if there was something stupid I was missing before I shell out a chunk of change and hope it wasn't tune related!

 

If it helps, here's an engine bay picture. The dizzy is still there, it just has the CPR kit on it

 

If it helps, whenever it is really warm the car behaves perfectly. For example, today is 70 degrees and the car has run perfect without any issues. It was 40 the other day and it ran pretty badly. Big difference. Any correlation?