Im sorry if its a common problem but ive been searching for hours with no satisfaction

I whent to pick up my girlfriend in my 2002 veloz and it lost power on the highway, i took an exit and it idled rough and the header was bright red.

I wiggled sensor plugs and let it cool and i continued down the highway and picked her up.

It worked fine in the city for 20 minuts and repeated the problems on the highway again. Now i can drive it aslong as i keep it below 2500rpm. As soon as it hits vtec it backfires, loses power and seams togo into limp mode.

So the short version is
Drives okay under 2500rpm in all gears
As soon as the vtec light comes on it sputters backfires and loses power so that its un driveable and turns the header red.

Car has a hot air intake, and full exhaust. No more silencer tho it backfired and ripped it out of the muffler

My first move in the morning will be air and fuel filters and plugs

If you guys have some seggestions ide love it hear it! thank u

 

My two Dailys

 

it must be throwing a check engine code with that kind of severe problem, have you scanned the computer for stored and pending codes? might point you to an issue...

operationally I've never looked into what's different in the VTEC maps that would cause this sort of issue. Does it happen for sure ONLY at the VTEC crossover? I think VTEC crossover is 2700rpm isn't it? or is it more 'close' to crossover? what about when the engine is cold, will it go past 2500 rpm without issue when cold?

is only one runner on the header red hot, or the whole header? will it rev past 2500 without issue in neutral (no load)?

 

Thank you!

 

It was a Tdc sensor (Cam position sesor)

 

Thank you for coming back with a solution! most people haven't the courtesy to 'pay it forward' for others seeking this info.

did the check engine codes point you in that direction?

FYI, it probably wasn't doing it because of VTEC though. that was why I asked if it does it in neutral and when cold. neither of those conditions will allow VTEC to engage.

 

No problem! Vtec had nothing todo with it, and the code reader told me the sensor was malfunctioning