Car fires right up then the idle drops and stumbles and almost dies,but doesnt.Give it gas to hold higher idle and it has a miss to it.Does this for a few minutes sitting in garage.Drive it to the closest stop sign and take off,slight miss,next red light it`s gone,idles and runs fine.No codes or ses light.Smells a little rich.I need to put a scanner on it to see what its doing,but I dont have one.I`ve read modifying the maf sensor causes problems which I did years ago but this is recent.coolant temp sensor?cold start injector?burn off relay?Engine,plugs,wires,cap and all have less than 10,000 miles or less.I am getting carbon build up in cap already,and have changed the plugs a couple times cause they looked like they`re fouling.Thanks

I think the CTS sounds right. That can do all sorts of crazy things to an idle, and make it run rich.

I have two sensors up front where the cts is.I believe the smaller one is the cts.What is the other one the plug on it seems like it may not be good.

Also when I unplug the iac the idle seems to clean up a little.The four pins that come out of the IAC also seem like somethings wrong there.Two of the pins have a plastic black sleeve.the other two do not.After I drive the car and park it it will crank up and run fine,but if it sits for a while,like an hour,It has a starting issue where I have to crank it more and give it gas to get it to start.If I dont it will turn over and die.But as soon as it starts it idles and runs fine.

Or could someone tell me what to search under.I`ve been surching but found no problems like this that aren`t setting codes.When I unplug the cts the ses comes on but the car runs the same.anyone got anything.

I just got my aldl cable and started dattalogging for the first time.Hopefully someone can help me with some of this information.I was pretty sure I had a rich problem.On the flaged data screen I had a closed loop flag,and a blm enable flag.I had a blinking on and off intermitten rich flag and an eecc slow O2 rich/lean flag.My ses light was not on but on the error codes screen it checked the coolant temp low box.Temp was about 180.What other info might help?IAC was 84 to 86.tps was 32 at 63 volts and 2.1 what ever all this means.Might it be the cts.Any help will be greatly appreciated.

Please post what you come up with. I've got the same exact problem. rough idle, tries to bog out, sometimes does for 3-4 minutes, then after warm-up, runs fine. I've reset the IAC and TPS, and checked the CTS but can't come up with anything. I'm about to take it to a mechanic if I don't come up with anything in the next month. Let me know how it goes.

Jim

Just curious,Have you modified your maf sensor?Does it smell like your running rich?

Nope... everything is stock.. I'm going to try to set the timing this weekend, but i can't imagine that would F up the cold start that much, since the car runs fine when warm.

Heres what I found.I got to thinking it`s running rich,maybe its a weak ignition system.I thought I should have a good hot ignition with what I got so I started checking through the msd wiring.I found a couple of not so good connections.One was hanging on by two strands of wire to the connecter.I fixed all that and fired it up.Still a little rough but it cleaned up quicker than normal and the fuel smell was much less than normal.Put on a coolant temp sensor and waited 3 or 4 hours before I cranked it.Fired up with out stalling and wanting to die.It stumbled just a little,but I`m hopeing the plugs might clean themselves up a little as it runs with a better connection to the msd box.So I believe most of my problem was just a weak ignition but for 17 bucks the cts couldnt have hurt it.I changed the pigtail too.

The other one is the cold start temp sensor, watch out they are expensive. Chevy wanted $114 our here in Cali. and you are correct the small one is the cts.

could the cold start temp sensor be the problem.Fans run all the time.New cts didnt change anything,no codes.

It may be, i know that mine was running very poorly but my tps, cts and csts were all bad amongs other things. but if it is, the cold start injector won't know when to work and the computer will just dump fuel to compensate.

Just realized I never disconected my battery after I changed the sensor.I did it and that seems to have fixed it .No cold start rough Idle anymore and the pig rich problem is gone.Thank god.

Has anyone figured this out? I've replaced the small CTS on the front of the block, and I've reset the IAC and TPS a dozen times. Only problem is the cold start.
thanks
Jim

After you did it did you dissconect your battery to reset the computer.