i swapped a jdm d15b sohc 16 valve vtec into my 93 cx hatch, i bought a chipped and programed p28 but it kept throwing cel 21, i replaced the vtec solenoid and same thing.i tried my friends p28 out of his 93 del-sol si and ran fine with no cel. since then i have sent my chipped ecu back to the seller for another one. i was wondering if i could run my po5 ecu until i got my p28 back? i know it wont have vtec. i was trying to save some gas money by not driving my 98 suburban 454 9 or 10 mpg to and from work.