I recently got the EGR system in my 1998 Rav4 working (replaced VSV) after driving with it non-functioning for several years. Without the system fuctioning, the engine ran great, but fuel efficiency suffered. Now, when the engine is warm only, the engine knocks and luggs between 1000 and 2000RPMs. This usually occurs right when I shift into 2nd gear. There are no engine trouble codes. Any ideas would be appreciated.