1990 Chevy Lumina runs rough

1990 CHEVROLET LUMINA
100,010 MILES • 6 CYL • 2WD • AUTOMATIC
Avatar
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
1990 Chevy Lumina v6 3.1, mileage: 100,010. It labors badly after changing into drive and overdrive. I have no codes; my scanner showed incorrect volts at map and barometric sensor, the spark plugs are burning a touch rich. I used a vacuum pump on the map sensor, I didn't hear any change In the Rpms when I applied 20 inches of vacuum to it, but when I let the pressure off the Rpms did change.
Jan 18, 2011 at 6:43 PM
Advertisement
Avatar
2CP-ARCHIVES
  • MEMBER
  • 4,540 POSTS
If a major tune-up has not been done recently, that could be the cause. Replace the spark plugs, plug wires, fuel and air filters, etc. Also, replace the oxygen sensor. In addition, service the fuel injection system. Clean the carbon deposits from the throttle bore and idle passages. With 100,000 miles, you may have a partly plugged catalytic converter.
Jan 20, 2011 at 10:19 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.