rough idle/cold but runs better warm

[billsyzfr-1]

I have a 2000 Catera, 90,000 miles on it. Last winter I had a few times that I'd start the car, it would go to high idle, and then when it should idle down it would just die. I'd re-start the car and everything was fine. No problems in the summer, but now it's cold again, and it's the same, but steadily getting worse. I've developed valve cover gasket leaks, so I have them. New plugs are going in as well. I've read on here that the leaks can cause mis-fire codes. What I have now is 300-306 mis-fire codes. I'll start the car, high idle and then die. Sometimes it will idle really rough, at around 300 RPM's. Touch the gas and it's dead, shuts down. When I start it and it goes to cold start high idle, I can feather the gas around 3000 RPM's and get it warmed up then once the temp guage moves, it's better. Not great but the car can be driven. Can someone please help me with this issue before I put tons of cash into it for a possible easy fix. I did the Passengers side plugs, black from being rich, expected from all the mis-fires. Not much oil around the plugs. Is it an intake leak? Appreciate anyone's advice.

[Warez]

When my MAF sensor went it was causing the exact idle problem you described which would disappear once the engine was warmed up. I was also getting misfire codes. Have it scanned and check for rich/lean fuel trim codes.

[bK caddy]

im kinda havin the same problem
u might need to change the belt tensioner im changin mine this week ill let u know

[wamanning]

i also had this. cleaned the MAF...helped for a couple weeks. replaced MAF...been fine for a long time now.

[bengsxr]

Originally Posted by bK caddy

im kinda havin the same problem
u might need to change the belt tensioner im changin mine this week ill let u know

I want to know why you are changing this out to correct the problem.
But I will also mass air flow sensor. Test it before you buy a new. To test it with the car off unplug the mass air flow sensor then start the car if problem is gone then the mass air flow sensor is your problem.

[Resilient]

FYI: Cleaning the MAF

http://www.fordscorpio.co.uk/omega.htm
http://www.fordscorpio.co.uk/cleanmaf.htm

http://www.fordf150.net/howto/clean-...low-sensor.php

I did notice that one article suggests using ELECTRICAL CONTACT CLEANER while the first article says to use carb cleaner.

[bengsxr]

most people that do clean the mass air flow sensor end up changing it out within the next few months cause this is just a crutch to avoid the cast.

[caterashaker]

Resilient, I'm pretty sure that they meant ELECTRICAL CONTACT CLEANER because using carb cleaner on almost anything electrical is not a good idea and the MAF is an eletrical componant.

[wamanning]

Originally Posted by caterashaker

Resilient, I'm pretty sure that they meant ELECTRICAL CONTACT CLEANER because using carb cleaner on almost anything electrical is not a good idea and the MAF is an eletrical componant.

that makes sense to me. wish i'd have known about this stuff before i replaced my MAF!

[billsyzfr-1]

I appreciate all of your help from each of you. I did remove the MAF, and runs great. To bad no one other then Cadillac has it in stock. I'll order it online. Once again, thanks for all of your help.