Somethime my engine idle as 200RPM to 2000RPM at 1 Hz, and then after 1000 to 1200RPM at 1Hz and then by hazard oscilate again between 2000 to 2000,,,, and often stop... Went i drive couple minute at crusing 3000RPM then a stop at a STOP , i release the gaz,, them engine stall grrrrr What is that trouble ? idle valve or something ? Denis