98 camry--starting problem

Hi,

On cold morning i always have a rough start...i have to press the ignition key for atleast 15-20 seconds before the car finally startup.
I replaced the battery,pcv valve,ignition wires,spark plugs 4 months back but still the same issue. I talked to one mechanic and he mentioned that it can't be starter since car is cranking for 15-20 sec and he mentioned it might be one of few things:
1) throttle body sensor
2) fuel injector
3) idle mode
What is idle mode since he mentioned it will be 450$?
the other parts need to be replaced or just requires cleaning?
Any other suggestion what can be wrong?

Thanks
--rubs

More to add..I called 3 diffeent dealers service department and all give different reasons on phone:
First:
Throttle body sensor
Fuel injection
He says can't be starter since cranking
Second
May be idle mode
Third
Alternator or starter
Cant be sensor or fuel injection (he says the check engine light should be on)

Not sure where to go?

Thanks
--rubs

What engine do you have in your car?
Idle mode is different for different Toyota engines. ICS, PCV.
Try to get read out of your computer. With some engines you can do it your self (shorting two connectors and watching check engine blink). You'll get 'code'.
What temperatures cold?
What viscosity oil do you use for your engine / trany (if manual)?
Is the starter turning 'fast enough'? (Compared to summertime?)
Don't want to scare you.
:-)
Most of time, proper adjustment of underpresure is enough...
BTW: Did you try just the basic timing adjustment?

Majoo,

Thanks for reply. Can u explain this 2 points in brief:
Most of time, proper adjustment of underpresure is enough...
BTW: Did you try just the basic timing adjustment?

Thanks
--rubs