Well it popped up again. I was doing some spirited driving around some backroads here. Went WOT for a bit off and on, while I was decelerating in vtec at about 7k at very low throttle about 10% when the CEL popped up and the kind of jerked forward a bit.

The same thing happened a while back about 3 months ago I was creeping up to 6k, wanted to do a 20mph kick just for shits and giggles and the same thing happened, I was in vtec for about 2 seconds before I WOT the car jerked forward and CEL popped up. I got the code pulled as vtec system malfunction, erased it and car drove fine since then.

Im thinking its the same thing this time, but when I tap the gas a bit till about 2k the idle drops really low to like 400rpm and the car shakes then rises up to 900 and idles fine there.

I do have a vafc2 but its only tuned for WOT. The car is leaned up top quite a bit. Is it possible that when I go from WOT to low throttle (tune to untuned) maybe the car is being too lean to be in vtec? This never happened before I got the VAFC2. Only thing that I might not think its the vafc is because of the weird idle that drops so low then rises only when you tap the gas. Maybe an IAC issue? But that wouldnt affect vtec would it? Ill be getting the code pulled tomorrow I was just curious if anyone knew what this could be since 'vtec system malfunction' is kind of broad.

 

The idle could also be the MAP sensor. Mine is doing the same thing where it almost dies, then goes back to normal. Maybe you have 2 issues?

 

But it does it fine any other time, it only does that when the CEL is present. Last time I reset it and the idle went back to normal. Why would it only happen when the CEL is present?

 

I got the CEL checked and it turned out to be air/fuel metering system. The car now idles like crap, really low like around 500 or 400 and shakes but it does go back to around 800. The car died on me once since the idle was so low it just turned off. I erased the CEL but the problem is still there. Could it be the O2 sensor on the test pipe?

 

I was gonna say maybe the ECU is running to safe mode, but seems like the problem now persist even when the CEL is off?

 

At first I reset ECU by pulling the fuse and that didnt do anything. I erased the code and the car IS running a little bitter, still idling a bit low at 700-800ish. But it doesnt shake or die at a stop. The CEL hasnt popped up since I erased it but I still wanna make sure its nothing major.

 

Alright well the car is running fine now, why is it only when I erase the CEL that it runs fine. What exactly do I need to do when the code read air/fuel metering system.