Rep Power: 0

Hello all!

Im a new member and recently a new owner of a 2006 civic si. I had a 9th gen but someone totaled it out

So basically I bought the car with a really weird issue. What happens is if your full throttle, right at 4k rpm you can feel it lose power a bit but it doesn’t feel like a misfire and there are no codes but a lean code. But if your before like 3/4 throttle it accelerates just fine past 4k and you can feel is has more power. It does hit vtec consistently at 6k even when it feels like it’s losing power, so it can’t be anything with that. This car also looks like it had a turbo at one point, with the heat wrap all by where the turbo would go, and the drain bung on the oil pan.
Speaking of the lean code, my fuel trims are also at least +35% all times no matter what you do, even at idle.The weird thing is all the other live data seems to check out, and it runs very smooth and idles good, also starts right up every morning no problem. I thought because it was turbo’d at some point, maybe they didn’t tune it right when they put it back to stock? So I ordered a stock ecu, and it will be here friday. Anybody got any other ideas? Listed below if everything i’ve tried/tested so far. (Car does have low mileage 87k and also a dc sports cold air intake and magna flow street series 2.25 exhaust)

checked fuel pressure (load/no load doesn’t go below 50)
checked fuel volume
checked maf values seem good
swapped intakes
cleaned fuel injectors/good spray pattern
no vacuum leaks
no evap leaks
checked compression, leak down
checked ignition, everything looks good
checked AF sensor response

Any insight would be a great help! I need to pass emissions in 2 weeks ! LOL

 
Rep Power: 221

I would guess something to do with the tune. Not something I've messed with though.
I avoid buying previously modded cars

 
Rep Power: 223

Did it come with Flashpro or something?

Does sound like a tune issue.