N/A Ka24de has lag and feels sluggish

[jazz4890]

I am creating this thread because I am having some problems with my car feeling like it lags then goes but when it goes it still feels kinda sluggish. It happens mainly when the motor is cold and just getting started up. Sometimes it happens when its warm but not as much. Also sometimes like once in a while it will start up and drive with no problems like no lag or anything it will feel like it has the power its supposed to but only for a minute or 2. I seafoamed the car before I did the new oil change as well and I seafoamed my aicv using the intake hose that goes directly to the aicv. The only things I am thinking that could be causing my problems would be maybe fuel pressure because I never hear my car make any hissing sounds when I open my gas cap. or it could be my gas cap its self not holding in the pressure but im not sure if that would really make a difference or not. Also with my idle I set it using the fsm and I have done my base timing on my own so I know its dead on. When the engine is cold and the air is cold and I first start the car up it idles at about 1,3000 to 1,500 rpm then once it reaches normal operating temp it idles at 750 with no problems. the only weird thing with my idle is when I press my brakes the idle will drop down like 200 rpm but its never enough to kill the engine but it drops down to about 500 rpm sometimes when I press the brake pedal while im stilling still. I have I have a stock ecu that I dont think is causing my hesitaion because sometimes the car runs good randomly. and my check engine light comes on like it should when something fails. Also my check engine light comes on randomly sometimes but it will only stay on for about 1 min or for about 1 mile of driving then it turns off. I have listed below all of the things I have recently put on and done to my car to fix my hesitation problems.
New o2 sensor
Brand new OEM tps sensor
New spark plugs
New oil change with royal purple,
I have a brand new Coolant tempurature sensor
Brand new NGK Spark plugs and spark plug wires
New 300zx tt fuel filter
Brand new 2 month old fuel pump
I also have an intake and exhaust and a vlsd and a short shifter and stage 3 clutch but I know that isnt making it lag like that. The only thing I havent changed is my cap and rotor and I will be changing that in the next day or so as well.

If anyone has any info on what the hesitiaion could be I would love the insight and if you need more info from me to help out with my situation I would be glad to give it. So if I missed something to help with figuring out the problem please feel free to let me know. Also if anyone knows why my idle goes down when I press my brake pedal I would love to know what that is to thanks.

[S13_RB25]

Um about your rpms dropping when you press the brake, thats normal. Also for the lag or sluggishness, I would say check your timing and does the car have any type of cam swap?? Cause a 248/248 cam swap makes me feel the "lag" under 3k rpms, after that it pulls nice. Also did you gap the new plugs??

[jazz4890]

Thanks for the reply and I know my timing is dead on because I replaced my front main seal 1 month ago and I redid my timing then. I dont have a cam swap done the head and block are all stock. and with the new plugs I did not gap them no. but when I installed them they were pre gapped to .44

[S13_RB25]

Re-gap the plugs. The ka spec, IIRC, is from 0.38 to .043.

[OutToWinPAHC]

Or replace the booster because the diaphragm can tear in the corner causing a brief vacuum leak

[jazz4890]

Yeah I Re-gapped the plugs to .41 and it didnt make any noticable difference and I am going to replace my brake booster once I get enough money to buy a new one and see if that helps either the brake problem im having or the the lagging problem im having.

[hessianben]

this isn't an isolated phenomenon. I have a truck with the same ka24de, and have gotten in contact with a handful of other ka-powered vehicle owners who have experienced these symptoms in the last month. curious to see if anyone can track down the culprit... I've already gone through the fuel system, timing, maf, ignition and reset the ecu, all with no improvement. the strange thing, is that i had not changed a single thing on my vehicle before this began. drove to work, plenty of power, started up after work, fluctuating idle, bogging hard (feels like brakes are depressed) between 2500-3100 rpm, and overall lack of power through rev range.

[compactfean]

What code is your ecu throwing? With the check engine light on, that should point you in the right direction (even if its not on right now it should still store the code. I would be looking into knock sensor or knock sensor wiring issues.

[hessianben]

mine's not throwing codes at all- obd2 wtf??

[compactfean]

I've seen clogged injectors (to the point of needing them professionally cleaned) cause issues like this with no check engine light. Same thing with mafs that are going bad.

[jazz4890]

Yeah I will check my ecu's stored codes and see what I get with that. And about the injectors being clogged you could be right about that because on this same motor an injector just stopped working and I was only running on 3 cylinders then I replaced the injector and everything was fine then it started getting sluggish again like 2 months later so maybe it is my injectors being slightly clogged. Ill definetely be checking that out as a possibility. Ill let you guys know what I come up with.