help! hard starting, higher idle

[BMW_sauberf106]

ok, car ran great after a headgasket change for 4 days. but it did have hesitation when I blip the gas at idle. it was idling at 700-800 rpm.
now it idles at slightly higher then 1000 rpm and it has hard time starting.
it will only start when I press on the gas pedal, it sputters  then dies. if I do get it to run, it pumps out white smoke( it does not smell like oil or coolant and all the fluid level is fine) for a good minute and then it goes away for good. I dont feel any power lose or hesitation unless I blip the throttle.
I have checked all the vaccum lines and replaced all cracked ones.
any ideas???

thanks

[Febi Guibo]

check yer throttle cable, linkage and springy thing ...it may have slipped or its binding... if those are okay, take the throttle body off, check it real well and clean it with carb cleaner, same for the afm.

[Jtuner]

Make sure all your vacuum lines are connected and there's no small cracks in any of the big ones.. Use a can of carb cleaner and spray around the engine bay while its running (if you can keep it running) until the engine flares up, or dies instantly.. You can isolate a lot of vacuum problems with that shtuff if you wanna keep it simple and cheap

[BMW_sauberf106]

ok, I've checked all the vacuum lines. they are good no cracks or pinched lines. I've sprayed carb cleaner and even checked it with vacuum pump and it's all ok. swapped the afm with the spare, new plugs but no difference.
i got a good sniff of the white smoke and it's unburned fuel.
I've noticed that car will start a lot easier with the Idle control valve hose disconnected from the intake manifold and gas floored, but it still will not hold idle. I am going to take it out and check it tomorrow.

thanks for all the help and please keep them coming!

[BMW_sauberf106]

ok. I've had the car hooked up to BMW GTone(modic), and it is not reading any faults. I've changed the dme, injectors, fuel pressure regulator, air flow meter, Icv,  checked all vacuum lines but no fix.
So far I know that the engine is getting enough fuel and spark. and it will only start or sound like its about to start when I have the throttle wide open.
so the engine is not getting enough air.
any ideas?

thank you in advance

[Vladi]

Did you check the TPS sensor?

[BMW_sauberf106]

I saw thinking of the TPS too. Do you know what resistance reading I'm supposed to get?

Thank you

[BMW_sauberf106]

problem fixed!! it was a faulty coolant temp sensor. I guess the GTone did not reas the fault.

thank you everyone for your help!