My VVT(vtec) won't kick in

[Adnan]

Hey guys,for the past month of so when I go full throttle it picks up just fine until I hit 4000 rpm where it jerks as if I let off throttle and slowly climbs to 6000 rpm then shifts to the next gear.If I let off throttle even a bit I instantly lose power and acts as if its about to stall.If i repeat it several times it improves but I still dont hear vvt engage in most cases.I recently changed the oil so its at level and im not getting any codes. any suggestions??01 pathfinder with 3.5

thanks!

[pathfinder9035]

is the check engine light on?

And pathfinders with teh 3.5 dont have Vtec.

[Adnan]

no i dont get any codes

and im pretty certain the 3.5 has vvt

[Pwnin O'Brien]

Yeah, no VVT until the 4.0, unfortunately.

[QX4ME]

I am not sure but below is what I read somewhere:

Question: I have a 2002 Infiniti i35 it has 53512 miles. a service engine soon light came on . I own a scan tool got a code. it is P0021 Camshaft Position - Timing Over-Advanced or System Performance (Bank 2) is this some thing that a could repair my self or would I need to take it to a repair shop - Esquivel, August 2008

Answer: Hi Esquivel, thanks for the question. This P0021 trouble code refers to the components of the continuously variable valve timing (VVT) system (new for 2002 3.5L engine). Potential causes could include incorrect camshaft timing, the VVT valve/solenoid could be working improperly (stuck, etc.). There could be other potential VVT related components that have failed as well. If you're up for the task, be sure to get a good (OEM) repair manual and read up before taking anything apart.---------------------------------------------------------------------------------------------

Although thwy were talking about I35, should the engine be the same as QX4/Pathfinder? My window sticker does not say VVT.

[Pwnin O'Brien]

I stand corrected.

P0021 - Intake valve timing control (IVT Control)

This mechanism hydraulically controls cam phases continuously with the fixed operating angle of the intake valve. The ECM receives signals such as crankshaft position, camshaft position, engine speed, and engine coolant temperature. Then, the ECM sends ON/OFF pulse duty signals to the camshaft timing control valve depending on driving status. This makes it possible to control the shut/open timing of the intake valve to increase engine torque in low/mid speed range and output in high-speed range.

Essentially it is variable valve timing for the intake valves.

[pathfinder9035]

Vtec is different than just having VVT. The 3.5 does have vvt but it isnt electronically controlled like the new nissans which has a different name now..VVEL for variable valve event and lift. Vtec is honda, and toyota has vvtl-i. teh 3.5 for out pathfinders just have VVT which is hydraulically controlled.

correct me if im wrong.

[Adnan]

something along those lines...im not saying vvt and vtec are indentical just different names.Its the same principle but using different approach

but yeah lol... help?

[Pwnin O'Brien]

Well if you aren't getting the MIL, then I would suggest checking some maintenance related items. Probably the first thing I would check would be the fuel filter and fuel lines. I would then check the air filter and air box to ensure proper ventilation (although that would probably throw a MAF code). It sounds like maybe your engine is getting starved.