Hello, I own a 03 sierra denali and just had a tune up with plugs and fuel filter with emission cleaned. every since I got it home it doesnt want too idle correctly in gear. it seems too clog up or rough in reverse and in drive without any gas being delivered. when its on highway it runs ok. oh also had a new drive belt on too. I am at a loss. if you can help a disabled vet with a few ideas it would greatly be appreciated. thanks Robert
