ok for some reason my vtec breaks up after the car has been running for a few mintues. if i start it up in the morning then let it run and go into vtec it works fine then if i try it again later it starts to break up like vtec is cutting on and off . it kinda sounds like im hitting a rev limiter but it keeps accelerating but losing power ive checked the oil put a new solenoid and pressure switch on use ddiffernet types of oil viscosity nothing has worked. i even got it tuned. any ideas. its like when the engine gets hot vtec doesnt work properly

 

no check engine lights?

 

How's you oil pan? If the pan is dented in from hitting speed bumps, it could be affecting the oil pickup unit, causing you to get intermittant VTEC. Also, check to see if the screen on the VTEC solenoid is clean and clear of debris.

 

change your plugs. mine did that too

 

i changed my plugs changed and cleaned the solenoid changed the oil and i dont have any real dents in the oil pan. its really been bugging me any other ideas? it only happen after its been fully warmed up

 

and no check engine lights

 

See if a friend will let you try their solenoid. If it acts up there, try an ECU.

 

I put a new dissy in my car and it was doing that, it would accelerate but as soon as it hit vtec it would break up, the rpm's would drop, I changed the coil and made sure all the wires were tight, and it pulls strong and hard all the way to 8200 rpm's.