Hi everyone,

I need big time Help here, This is the whole Story:

I did an oil change and also i changed my O2 Sensor for a wide open that emulates both narrow and wide signal, before this my car was pulling strong. I took it for a ride and push hard on it. on first gear, all good shifted to 2nd and right at the vtec point around 5000 or so RPM the car slowed down and makes this funny noise like choking i have my foot floored on the gas, and very slowly the revs comes up and suddenly the Vtec engages and power comes back.
It does all this on all gears but 1st.

I have checked oil, soleniod, screen on Vtec etc.

Now one thing i did notices is that if i'm not aggressive on the gas, but smooth i don't have this problem. never looses power, but if i floored it, car chokes and struggles to go past 5000ish 6000 then power comes back on.

I have though of most and can't find the problem only thing now i'm lining to is the O2 Sensor. that gets clogged or something, as when this happens there is heavy smell to smoke o fuel. can't really tell.

Any comments and feedback will be much appreciated

 

first check your spark plugs how they're burning, if they ash color then your car running lean in vtec.
Any mods? stock ecu or chipped?

 

Hi,

I have build the engine for boost, that means, forged pistons, connecting rods, camsgears camshaft etc, i broken in properly and car was working good, so i started to pull hard on it, with Zero issues, then it was time to replace the oil after broken in, at that time i replaced the O2 Sensor for my wide band, wanted to monitor the AF before slam'n the turbo in it. and also replaced the ECU S300 on it. as soon as this happen i changed it and put it in the original one, with same results.

Any other ideas besides the Sparks, they indeed ash colored

 

By the way, after i rebuild the engine, car was running good, it run bad ones i changed the O2 Sensor and the ECU, i used stock map on it. then i swapped to OEM ECU still doing the same. so that is why i'm blaming the O2, but could be i'm running lean i'll record one run on data log and see what happens.

if you guys had have something similar, your feedback will be much appreciated