Runs like a dog when cold

[amg]

Ok, so it's getting on a bit now and it's to be expected, but when it warms up it actually runs beautifully.

So what tips can one advise during the oncoming winter months to make your typical 6 pot VT handle the cold better without having to sit there warming it up in neutral for a couple of minutes.

 

[EYY]

Check for fault codes to start with. You should be able to jump in, turn the key and drive it straight away without any hesitation or problems.

Plugs, leads and coils would be a good starting point.

 

[Bowen]

Check for fault codes to start with. You should be able to jump in, turn the key and drive it straight away without any hesitation or problems.

Plugs, leads and coils would be a good starting point.

This and probably just a good service paying attention to things like how old are the oxygen sensors, when was the last time the maf was cleaned, clean upper intake (paying particular attention to iac stepper motor), reco injectors, fuel filter, check fpr, check all vacuum lines replace all of them if your unsure of condition (they're very cheap) you know that sort of thing.....

Yes it's probably not the direct answer you want but I guarentee your car will run much better

Cts might be s good start, they're about $25 (that's the one which I out goes to the ecu not the temp sender for dash) could be telling the computer your running normal operating temp causing the car to run funny as it's still cold and the pcm has leaned it out ....

Vac lines definately worth a check (any vac problem will be exaggerated when cold)

And clean your upper intake

This stuff is all inexpensive and even if not the culprit You can rule it out and it probably needed it soon anyway

Hope that helps mate

 

[amg]

So I let the engine cold sink for a few days and had a look.

CTS and ATS appear to check out fine and the resistance correlates with the ambient temperature.

I noticed the rubber in the hoses were getting hard so I pulled off a loose one out the back of the plenum chamber and cut off the bit that had hardened in the shape of the pipe OD and refitted it, it's a much better fit now.

Next up I may take the serpentine belt off and see what is sticking when cold.

I've noticed a bit of corrosion around the base of the EGR valve, I did replace the gasket some years ago, it sits solidly enough on the base though one of the nuts is completely corroded from heat stress. Maybe it needs a new gasket although I can't hear any leaks.

MAF and IAC was cleaned a few weeks ago, no difference as they weren't too bad to begin with.

Could be spark or vacuum leak, I'll get to them in the next maintenance due in a several thousand K's.

Bit of a shame as it runs extremely well when the temp needle moves off the C.

 

[NeddyBear]

Replace all the sensors, we did and it runs really smooth.

 

[BlackoutSteve]

Vacuum leak will produce rough running when cold and can be almost un-noticeable when warm.
Had some banana service and fit the wrong O-rings on my injectors a while ago.
Was a real pig cold, but ran well and smooth warm.
V6 intake gaskets are notorious for degrading and leaking a lot.

Checking for leaks would be the easiest, cheapest and first place I'd check.