Cold sputtering when applying throttle?

[yieldsign2]

Well, I'm a little lost of where to go now. Only when it's cold out, for the first 30 seconds of running or so, it idles a little funky, and if you hit the throttle sharply, it almost dies , then picks up and goes. After about 30 seconds of driving, it's fine.

I've already replaced:
Engine temperature sensor
Temp sensor for gauge
Throttle Position Sensor (non adjustable)

and I've cleaned the whole PCV system.. I don't know where else to look. I do have pretty bad exhaust leaks (after the cats), could it be just a backpressure (lack thereof) thing? Where would you go next? I guess i could throw plugs or s distributor cap at it.. But i don't like throwing parts at it.. I'd prefer to diagnose it.

[TerryS]

Before you start it next cold morning, pull off the distributor cap, and rotate the rotor and let go. Does it spring back to it's rest sharply, or sluggishly? The pivots for the advance weights may be gummed up, or frozen. Check that and come back.

[OkieRover]

Is your air idler valve clean?

[Greg M]

I ran across this old thread when i was searching, so sorry to resurrect it, but mine is doing the same thing, especially the colder it gets. If I let it warm up a few minutes its not quite as bad. If it was a carb i would blame it on the choke, but who knows on these new fangled fuel injections.

So Devon, did you ever figure this one out?

[RageRover]

Could be what Okie said, IAC could be dirty, I know mine was, and afterwards it ran better.

Injectors could also be gummed up and once the truck warms to closed loop for fuel operation it would run better. A good decarbonizer might help...mine definately improved after I did it myself at the college.

Also the throttle body could be dirty as well.

[kickinitonthecouch]

hum....kinda new to here but if my truck and wouldnt run when its cold and runs fine warmer then i would just let it warm up longer.but here where i am its below 0 right now

[RageRover]

Hey Kickini....

Does your truck even start in cold weather like anything below 40 degrees?

If so, how does it run...like what symptoms are there if any?

It could be a bad Coolant Temp. Sensor. Or clogged IAC. Injectors too could be a cause...also I forgot about spark plugs....some plugs warm up slower or faster than others, just something to check. Also check the gap on them suckers.

I will get a better idea once ya respond...best of luck!

[yieldsign2]

Nah haven't figured it out yet. Renovating the truck again this winter.. so don't really need to figure iet out until next winter since I won't be driving it.

I am somewhat worried if it is broken teeth or slack in the timing chain/gear, as someone said you would get sluggish response from that, and my old one acted strange when cold up until the chain went. Probably will try to do a chain job before i put it back on the raod to make sure.

[daway]

hello, 1st start by cleaning the stepper motor like okie stated, also clean or replace your pvc filter, then sea foam the the rover through the induction system and see what happens. i had the samething the 1st winter after i got my rrc (05) and i would start up then if i hit the gas it would take 5 seconds or to kick in. it went away in the later part of winter in 06. i had the spark plugs, cap dist changed. i just cleaned out the stepper motor acouple of wks ago for the 1st time, sea foam the induction system last sunday. last spring i got a new pvc filter and crackcase filter. i will get u know how it goes this winter but it has not did that idle slow go since the 05 winter and i did not clean the stepper motor, or etc.

[Greg M]

Thanks guys. Its not the stepper motor. Not only is it clean, but it think it would still run rough at all temps. I was hoping temp sensor, but that's not it either since there's a new one in. Could be the hot wire in the MAF, could be the injectors. Whatever, its running lean.

I've been letting it warm up to over 100 degrees on the guage before i drive it. It's better, but still not right.

So Pat how did you "decarbonize" your injectors?

Daway, isn't it cold enough in MN by now?

[daway]

Originally Posted by Greg M

Daway, isn't it cold enough in MN by now?

it was in the 50 to 70's last couple of wks!!!! just went from 50's down to about 9 degrees today!!! u could check your fuel filter, fuel pump. get a bottle of lucas fuel injector cleaner and etc. try the sea foam in the induction system and clean or get a new pvc filter (clean out the carbs) i could feel a differnts after i sea foamed my rrc on sat.

[Greg M]

Originally Posted by TerryS

Before you start it next cold morning, pull off the distributor cap, and rotate the rotor and let go. Does it spring back to it's rest sharply, or sluggishly? The pivots for the advance weights may be gummed up, or frozen. Check that and come back.

Terry would you be so kind as to elaborate? Do you think the mechanical advance is sticking?

[Greg M]

Okay, I did as Terry had suggested, and sure enough the mechanical advance is stuck. Did my research and found this on rangerovers.net

http://rangerovers.net/repairdetails/misc.html#advance

Shame on me for not doing this as part of the routine maintence. Lesson learned.

[TerryS]

Originally Posted by Greg M

Terry would you be so kind as to elaborate? Do you think the mechanical advance is sticking?

Well, I guess you figured out that they were sticking, but hey, I've been told to go f**k myself before, but no one ever told me to go elaborate, especially since this is such a clean, friendly place.

[Greg M]

So are you going to elaborate or not? Ever taken one apart before? I am pretty clever at figuring things out, but any words of wisdom are appreciated.