i recently did a de-k swap and installed a vfc2 at the same time, the car ran great for a couple of weeks but now i notice after an hour of driving it sounds like a sti (raspy bogging sound you hear all those sti's make).until you cross 3,00 rpm. sometimes it will make it from start-up. i checked the maf and its fine, the vafc is not tuned as yet. as for mods its basic cattman headers, walbro 255 fuel pump, ijen cai, i do have a small muffler leak right after the y-pipe if that helps. rmp runs smooth across the band no issue with getting up to speed.

 

Sounds like either your maf is weak or you have a failing ignition coil.

 

Check your oxygen sensors also.

 

That's that is usually when problems occur. Uninstall the afc and see if the problem remains.

 

I've had the same problem too.

This approach makes the most sense:

While this does not:

But since you mentioned AFC, your best course of action is to remove it like said here:

My solution was ditching the DEK injectors (I just dropped the motor in and removed the power valve, not much modification) and using my stock DE ones.

 

Sounds like the injectors you got with the engine were clogged/stuck. I've flowtested a few junkyard sets and they took a round or two of ultrasonic cleaning before flowing well again.

 

Could've been, we will never know. One the first run the car was shooting fire crackers all day, but after about a few weeks it ran like the OP is saying.

Cold start was hilarious on untuned DEK injectors, sounded like a big ol chevy cammer until it warmed up, if I had a AFR gauge I'm sure it'd flatline out

I never cared much for my DEK swaps, they were all quick cheap and dirty projects.

 

sorry for the late response everyone, i appreciate any input given to solve this problem, im waiting for the weather to warm up, and ill fix the leak in the exhaust, install afpr, check the injectors and coil, i am running rich as hell 21.8 at idle and if im lucky 17's at wot

 

You mean lean



No wonder it's breaking up.