tim996

I have read this chain hoping for an answer.. none. I have the exact same problem, occasional stumbling starts hot or cold, runs like a pig for 30 secs then clears and is perfect.
Changed all plugs, all packs, maf, air temp sensor. Been to dealer, they checked for air leaks, nothing.
Done the durametric all looks ok, fuel trim ok.
What is really odd though.
If I unplug the lambdas it is is worse, but they shouldnt be read at start up. Also according to another OBD reader, sometimes my car starts in closed loop ( when it runs poor) and then is fine when it either starts in open loop or when it goes to into open loop.
Surely it should always start in open loop and ignore the lambdas, so why would unplugging them affect starting?
Please help as gone on for a year now and dealer stumped.
1998 996 3.4.

Funny about recent post, I had the feeling it was worse with high octane fuel, so I will run it on 95 and see if its any better. Why would this be?

seanmcr6

IT should only run in open loop when the engine/exhaust/o2 sensors are NOT up to temp. So if you ran your car for a while and turned it off...it will start in closed loop if everything is still warm enough....

tim996

thks, what is odd that it always starts in closed loop, hot or cold for the first 10 seconds, then switches over in open loop when it seems to be better.
Is this normal?
Also odd that the air temp sensor always reports -40C for the first 30 seconds before it shows the correct temp. I have changed this for a new one, but its the same.
like most things if your car is ok, you dont obsess with figures, but as soon as it plays up everything is a culprit.
It hasnt been too bad recently, what I need is the laptop connected when its being really difficult.