Engine Performance problem
1996 Buick Limited 6 cyl Two Wheel Drive Automatic 97,000 miles
I've checked and replaced and cleaned components, but idle and acceleration issues still exist. I replaced PCV valve, new fuel filter, and cleaned egr valve. I notice a burnt fuel smell, but no smoke. The car makes a light puffing sound. The car run rough, and shimmys at low acceleration up to 45mph. The car runs great on the highway at 70 mph. I put in some Marvels Mystery Oil in the gas and oil too. My fuel economy has been bad as well. Any ideas.