With a week left on the 7 year/200000 mi. and only 77,000 mi. my baby got all new injectors and is like a new truck to me! Quieter, no smoke at idle, no gobs of black smoke under hard take off. Thank you GM! Had it tested a year ago while in for water pump under warranty and it passed. If your time is getting close on the extended deal it pays to keep a close eye on it as this is probably a $3300.00 + fix.