A 2000 Cadillic Deville , the car is hard starting in cold weather, won't idle or it idles at a high RPM. When cold I sometimes need to stay in car so it will stay running at lease 5 min before it will idle on its own, or it will just run at a high idle 1100 to 1200 RPM with out droping. While running it will sometimes just stall while on the road, or it runs at a high idle. Now this is an issue that is becoming more an more frequent, but there is days that it runs fine. Im from the Northeast.

Mark Carrington

• 192 Answers
• Posted on Mar 09, 2010

SOURCE: 97 cadillac deville only overheats on hills it has

The most common overheating problem with the Northstar engine is a blocked purge line. It's job is to purge air out of the cooling system.
There is a small diameter hose coming from near the top of the coolant tank,this is the purge line.
With the engine idling,pull the purge line from the tank,if there is no coolant flow from this small hose,it is blocked and this will cause overheating.If the hose is clear, check for blockage at the nipple on the tank.Or trace the hose back until you find the blockage.The hose goes in to the engine to a crossover and comes out the other side to near the thermostat housing,the blockage may be there.

SOURCE: Very High Idle speed

no prob not and i had the exact same problem and bought the part from advance auto it was like $80 and it's a diy thing i'm an 18 year old female and could do it my self just need the part and 6 star screw driver...it's right there on the right side when you open the hood

SOURCE: dash codes on my 92 cadillac sedan deville are

throttle position sensor replace it. also in rare cases the map sensor will be bad . go to a junk yard and get your replacements it wont cost near as mutch. compared to the retail stores

SOURCE: 1991 deville idling very ruff

Hi you should change the coolant temp sensor this is a white sensor on top of the intake and is part ot the computer system.

SOURCE: engine runs rough especially on idle

I had same problem, and found the problem again in egr, replaced it under warranty and bingo.