Im having a problem with my 305 tpi. With the clutch pressed the engine revs before dropping in RPM. and if i come to a stop the engine lopes lightly but enough to stall it occasionaly. the engine also hesitates while attempting to accelerate from a stop and sometimes during regular acceleration. all this occurs only after the engine has been running for a while. I have no Vac leaks. I have replaced the IAC valve, the EGR Valve, and the PCV valve. I have also recently replaced all of the gaskets for the tpi system. it has speed densidy system so no MAF. my problem continues. any help is appreciated