My 01 has a really rough idle at cold start-up

[thrustn]

My car is a 2001 FFS coldside w/5th injector. During cold start-ups, I have to rev the engine to 2K RPM for a few minutes to keep it from dying. I have no problems with the idle after the engine is at a warm temperature. At my next oil change I am going try to switch from synthetic oil to conventional oil and see what happens. Anyone else having a really rough idle at cold start-ups? If so, how did you fix it?

Thanks,
James

[Banshee]

are you using a A/f gauge that is tapped into the factory O2 sensor? I noticed this when I tapped to O2 sensor.

[thrustn]

are you using a A/f gauge that is tapped into the factory O2 sensor? I noticed this when I tapped to O2 sensor.

No I'm not using an A/f gauge.

Thanks

[socal pat]

I did have this problem. I fixed it by adjusting the idle screw in the throttle body. Car ran fine when warm, but rough when started in the morning. Turned that sucker 1/2 turn and the idle didn't increase, it just started the way it was supposed to the next morning.

[Tom @ Fast Forward]

The 01-05 have an additional problem. Cold synthetic oil in the OCV (Oil Control Valve) for the VVT seems to not work well. I noticed it as well at temps below 40F. It took ablut 60 seconds for it to recover. I switched to regular oil and that and several other OCV problems went away. Not sure the OCV likes synthetic? Especially when cold. My 99 does not have the problem even with synthetic.

With the 05, if I start it cold and simply drive off, it seems to clear it's throat quicker. By the time I reach the first stop sign (ablut 2 blocks) it seems to be all well again. Was a lot better after switching to regular 10w30 oil.

[ThomS]

AS You guys know I have an 02 and I did have a rough idle at first, and had to run it higher RPM's to keep it going till it got warmed up also.
But then I set up the idle screw up a little bit of a turn and it seems to be ok.
I do live in Ohio so I get plenty of cold starts or I never drive my car,
and still using synthetic oil. Atleast so far. Idle ok for this year after Just starting the car Last weekend for first time after long winter sleep.

But to be honest I can not find any proof of any kind that Synthetic oil is better than dyno. None at all, just a lot of people's thoughts that it is.
So go with what works ok and Just change your oil every three thousand and your are ok. Besides dyno oil is so much cheaper.

What are any body thought on what oil you have used for Well since the car was new and then changing after the car has 23k on it.
this car has used synthetic from the beginning and changing to dyno some say it can hurt the car some how. IS this true at all?

[Kyp J]

Based on several articles I have read from more than one source, the 3,000 mile oil change is a holdover from the days before the exotic additives that have been developed over many years to maintain the
ratings that continually change and make the different rated oils specific for various applications. For example, air cooled, V twin motorcycles require different oil than water cooled, in line 4 cylinders; heavy duty diesel engines use different oil than gas engines, new small engine high reving cars vs. big block v8s etc.

There have been many tests done by independent labs that show changing oil every 3K miles is totally unneccessary unless you drive on dirt roads constantly or run at rev limiter constantly. Except for extreme dirt or heat conditions, normal dyno oil can safely go way more miles. I don't remember the specifics, but the only real way to tell if it needs to be changed is with analysis. Chuckerants did some of that I think. Anyway, the only reason to use synthetic is to extend the oil change interval even more by a factor of 2 or 3 times that of dyno due to its ability to keep the friction reducing additives from going away. I don't remember how it happens, it was a lot of chemical mumbo jumbo.

I think one of the sources for info. might have been from Mnet by a guy called "bobistheoilguy" or something.

The other source was from a diesel truck forum and magazine that I get. They didn't test the oil, they just reported on the tests done.

However, as both sources will show, it becomes a hot button emotional rant and rave when all the "experts" start nit picking and it comes down to "change your oil at what you think is the right interval". The oil companies need your money.

[elerner]

Thrustn, how long have you had the SC installed?

It's been a while since I installed mine but I remember going through some stumbling on cold start up as well. Like Thoms said, I remember having to raise the idle a little bit and going through the unplug/plug the IAC dance a few times. That plus giving the ECU time to adjust to the new conditions (2 weeks?) seemed to help with the low idle on start. Something else that seems to come into play is the location of the plastic restrictor. I originally had it in the hose right next to the IAC. When I moved it to right next to the driver's side valve cover that seemed to help a little.

[thrustn]

Thrustn, how long have you had the SC installed?

It's been a while since I installed mine but I remember going through some stumbling on cold start up as well. Like Thoms said, I remember having to raise the idle a little bit and going through the unplug/plug the IAC dance a few times. That plus giving the ECU time to adjust to the new conditions (2 weeks?) seemed to help with the low idle on start. Something else that seems to come into play is the location of the plastic restrictor. I originally had it in the hose right next to the IAC. When I moved it to right next to the driver's side valve cover that seemed to help a little.

I had the s/c installed about 3 months ago. I will try to adjust the idle screw first and see what happens.

Thanks