: HELP, service emissions eystem

09-06-04, 11:40 AM
I have a 96 Cadillac STS, I just had the head gasket replaced and two days later the service engine light came on and the message system says "service emissions system". The car cuts out like its running out of gas and I've lost about 15mpg. Any ideas? Thanks

09-06-04, 12:19 PM
Check to see what DTC's are stored and post them. Could be FPR, EGR, EVAP system, O2 sensors.

09-06-04, 12:51 PM
If coolant was being pushed through the exhaust system due to the failed head gasket, it's possible it contaminated one or more of the oxygen sensors. That seems like the most likely explanation to me, but anything is possible. The codes will tell us what's going on and someone should be able to tell you what to do to fix the problem. If you search the forums for "read codes," you will probably find numerous posts about how to check them. The "sticky post" at the top of the list in the Northstar Performance and Technical Information forum contains a link to a site that will tell you what the code means. It may be self-explanatory from there. Either way, let us know what you find...