ok my boy has a 94' gsr with a chipped p28...this is a problem that just started bc he was using the car for a good month before any problems...he can drive around for a good ten minutes or less or let vtec kick in and then the check engine light will turn on and no vtec...at first he was tld it might be the ecu bc no codes came up whent he diagnostic thing was hooked up...so he borrowed a gsr ecu and same problem then tried another p28 and came up with the same problem...the mechanic said the car was mechanicly good but had to look at the vtec solenoid...is it serious ($$$ wise) and any other ideas what might be wrong? thanks

 

check the oil level in the motor. also remove the VTEC solenoid and clean up the mesh filter part of the solenoid. it might be clogged with debree. do u have an oil pressure gauge to check the pressure? u might not have good oil pressure which is cauing VTEC not to come on