Hard lope on cold start

[tneibling]

Whenever dad lets his 01 (in sig) set over night then goes to start it the next day, it will lope really hard a few times then run smoothly. It will only do it the first time it is started that day. During winter it would lope extremely hard around 8 times before smoothing out and it was plugged in pretty much whenever it was not running. Today was nearly 80* outside and when he started it, it still loped 3 times then ran fine.

[tneibling]

Any ideas guys? could this be something ICP or IPR related?

[Dailey04]

Could be your injectors are not in sink until it warms up

[jesilvas]

Usually this lope is because of this:
"Ok here goes. Mine does it too. When it's cold (depends on the temp for each truck, mine is a wimp so 35-40 and down is hard), the oil is cold, so thick, so doesn't flow fast at all. Like cold molasses. But when you plug in the block heater, it does just that: heats the block. Which contains oil and coolant as well as the cylinders so everything flows nicely and combusts nicely too.
Well on each head there is a high pressure oil rail that feeds the injectors. The rail is only so big so cold oil can only flow down to the end so fast. AND it's a dead head rail, just an end, no loop. Oil enters near the front of the cylinders (#2 on the driver side) from the HPOP and gets pushed to the back (#8). Well in the firing order, #8 is RIGHT AFTER #6. So once 6 fires, it depletes what oil there is in the general area. Since the oil is cold, thick, slow, the HPOP can't push enough oil ALL THE WAY to the back of the rail to the 8 injector fast enough before that one fires, so it gets an incomplete injection. Just a normal engineering hiccup right and just has to be that way right? No.
You can either get some synthetic, an oil with a lower weight for the winter, or both. OR you can get a HPO Xover hose. Just bridges the two oil rails at the #3 to #6 cylinder area. So once #6 fires with that thing installed, you have oil coming from the HPOP AND the passenger oil rail to help replenish the rail before #8 fires. Smooths the idle, ESPECIALLY in cold starts. Makes it quieter. Keeps the RPMs very very steady. Had it on a dyno pre and post HPO Xover install. Pre install the RPMs on the comp were varying by about 50 or so. Post instal, didn't move at all. Ok, maybe 2-3."

I just wrote that as a generic post so it's got different stuff on there but you get the gist of it.
Not sure why it would still do it at 80 though

[Fred Swanson]

Mine does it when it's cold also, I just let it smooth out an warm up a bit before moving......Fred

[03haus]

Sounds like a injector is bleeding down.

[symbols]

There is a TSB on this. It said something to the affect that if you have this issue try a lower viscosity oil. I was using straight 40 when it would happen to me and I switched to 15-40 and it went away.

[tneibling]

Please excuse my ignorance, but what is a TSB?

He's been running John Deere Plus 50 15w40 since he got it which was a little over a year ago and it didn't begin doing this till last fall.

[symbols]

TSB= technical service bulletin

It was a fairly common problem and that was fords fix

[GM Duraturd]

Mine lopes bad for about 10 minutes when its cold and then goes away. I always wait till it stops to drive it beause it is completely undrivable when it is loping. Whats the deal with that? Its annoying, imbarassing, and a real pain.