Thanks for your reply. It is the infamous 4.3 liter engine. There are no history codes that I can find. The idle speed will should be about 750 rpms, but this one will go up to 2000 on an idle in nuetral. It happens quite often maybe 2-3 times a day. I am at a total loss as to what to do. I can’t afford to take it to a repair shop. Thanks again for any help.