1996 Cadillac Deville emissions system

JASONS CADDY

MEMBER
1996 CADILLAC DEVILLE

Computer problem
1996 Cadillac Deville V8 Two Wheel Drive Automatic

i have a 96 cadillac deville and the service emissions light came on. I brought it to the shop and they said it needed a new intake so I changed that and it went off for a few hours and then returned on again. Since this has happened my gas milage has went from 22 mi per gallon to around 13 or 14 at an average. It also blows white smoke when you first start it. Any help would be greatly appreciated thanx jason

1 Reply

FACTORYJACK

MECHANIC
4,159 POSTS

First, remove your upper engine cover and disconnect the vacuum line at your fuel pressure regulator. Check for raw fuel, you can even connect a vacuum pump with a clear hose to it and apply vacuum up to 20 in hg, also key it on or start it to build pressure. That could cause white smoke and a drop in mileage. Are you using any coolant, a leaking head gasket can cause the white smoke, and has been known to contaminate the o2 sensor and cause a service emission system fault.