: Check engine light won't go away???

08-14-12, 09:54 PM
Hey guys......failed inspection due to cat converter. Replaced with an aftermarket converter and also changed the spark plugs. The only 2 codes showing are for the converter which is replaced an old code for crankshaft sensors which i did a year ago? Why wont the engine light go off? I cleared all codes on dash... Also when i come to a stop theres like a shaking going on like a gas flutter... I need help guys thanks alot

08-14-12, 10:19 PM
Did you put AC Delco Plugs and Wires? These engines dont like anything else.

08-15-12, 10:29 AM
A steady SES light is usually an intermittent miss - spark or fuel related. A flashing SES is severe misfiring.

2000 Deville - divorced MAF - is all the intake air ducting properly hooked up and securely clamped ?? ANY air leak at or after the MAF will cause a nasty idle and may cause an intermittent misfire, which turns on the SES light.

Did you clean out all the plug boots, check the inner connector springs and use a tad of dielectric spark plug boot grease in the tip of each one ?

Cadillacs do not like aftermarket converters. Don't ask me why; it's black magic.

The CKP job - Have you checked the two electrical connectors for CKP's A & B ?

........ and, as vincentm posted, AC Delco #41-987 Platinum plugs only.

08-15-12, 10:33 AM
Exactly which codes are you still getting? Where did you get the replacement CAT?

Are the codes current or history? A year old CKP code should be history, if not deleted from history by now.