johnsnow

I had/have a problem when the car is cold and started the rpm will seek up and down between 600 and 1400 rpm 5 or 6 times, then settle fine. Also when cold in 2nd gear releasing the car hesitates a little

All the above pointed to needing a ISV clean, which I did last weekend and for 4/5 days it cured it (or possibly disconnecting the battery did)! However its not reverted back to doing the same behavour

Anyone any suggestions on what to try next?

techman1

John,

In my past experience, the cold, idle fluctuating up n down is something other than the ISV. Some others have said a rich issue may be to blame, but no experience with that.

What USUALLY happens with the ISV, it will open when a car is cold, and close as the car warms up. It does this to maintain a set idle, based on a pulse signal sent from the DME.

When you previously were using the car, it was warm, not much additional air was needed at idle to maintain the idle speed, so the DME probably had the ISV almost closed. If the ISV was sticking, it would stick at the partially closed, warm idle position. Next start, if cold, the sticking ISV would be closed too much, and a low idle would happen, not a high, fluctuating idle.

Shade tree mechanic view, keep in mind getting in the bright light sometimes changes the view!
(My way of saying "Hard to diagnose long distance")

johnsnow

Makes sense, would it be worth trying a new DME? If so is it 993.615.227.00

vincer77

^^That is the DME relay, not DME. Replacing DME is a bit premature. So the idle hunting behavior has returned?

pp000830

A slight cycling of the RPM on cold days, a small stumble on acceleration when the engine is cold or in very hot weather, an engine that uses some oil between oil changes, this is normal stuff.
A puff of smoke after sitting a while is OK.
Think “What would Jerry do after sitting a while?
And most importantly don’t go too deep, just enjoy the car!
You know the line, “accept the things I should not fix, have courage to fix the things I must and have the wisdom to know the difference”
Andy

fatmike

Clean your MAF (Mass airflow sensor). Disconnect the battery again and see if that makes a difference.

Plugs + wires new/new(ish)?

Or, as Andy said...live with it...


/

EMBPilot

umm would not turn a blind eye to this...

OverBoosted28

The car may not run optimally when cold. The trans also. If it runs fine, once warmed up, smile and enjoy it. Start searching for answers when you really have to. Like others have noted, way to many variables (plugs, dizzy/rotor caps, wires, maf, isv) to pinpoint what may be going on. The DME is constantly self adjusting to input and may hiccup for the tiniest things.

boman993

If the car is OBD2, (though, this may apply to OBD1 cars too), and you disconnected your battery during this ISV cleaning procedure. Make sure you allow the ECM to fully reset once the battery is reattached. I found that cutting all power to the car, the first few drives will sometimes stall the car at stop signs, or when coasting to a stop. Apparently this is normall ~ the ECM needs to re-learn everything and fully reset. I'd drive the car around a few times before investigating further.

Simple, but it may be the culprit! Hope that helps a little

johnsnow

I cleaned it weekend before last so its been consistantly seeking for about 8 seconds when starting cold since. Never not done it

I might clean the MAF at the weekend if thats worth doing? Is it worth cleaning the injectors also with some cleaner?

Not sure if it helps but the cars done 106k

vincer77

I find that when my car begins to stumble when shifting into 2nd when cold, a dose of Techron helps. The idle hunt sounds like ISV still.