Cold engine problems/driving uphill/vibrations

[Shadowfox]

Hi all... new here! Didn't know there was a site for us.

I've got a Nubira 1999 J100 X-Series 1.8L, and it has a real annoying issue on cold mornings. Ever since winter came along, it's been acting like complete crap.

The issue is, when cold, slightly revving it (just to 2500rpm), and letting off the accelerator, the revs drop very quickly and the whole car shudders when it drops (compared to when the car is warm and the revs drop steadily). The main problem is when going up a long uphill.

When I head up a long hill on the way to work, the car shifts down to the 2nd gear, and the revs hover around 3000rpm. As the hill continues, the revs start to fall. At this stage, my foot is to the floor as the revs continue to drop slowly. At the top of the hill, the foot is still to the floor, and the revs still drop, but slower than before. Letting off the accelerator, the revs drop and the car turns off.

After this, the car doesn't start for about 20 seconds (very sluggish crank). After this, the car starts, and it's fine.

If I'm lucky and don't travel on a hill, just before the thermometer is about to finally raise and pass the first line, when stopped, the car vibrates excessively. When accelerating off, it barely starts to move.

Once the line is finally passed (warmed up), none of these issues occur.

In summer, it NEVER happened.

I've tried the idle learning procedure, and it hasn't done anything.

Any help would be GREATLY appreciated!

Thanks!

[Shadowfox]

Forgot to mention, it's an Auto!

[john_trickle]

I'm guessing the MAF (mass air flow). It could just be dirty. That would easily give you the rough idle and slight shudder. If the coils were bad, the engine would really be cutting out on you with possible stalling and a very noticeable loss of power.

You can easily pull out the MAF(mass air flow) and clean it yourself. You need to first get a spray can of electronics cleaner. Something similar to this.
My best guess is to have the idle air control valve cleaned also I have looked into some threadsand found a recommendation to insert the key, wait 10 seconds for the lights to go off, give the sensors a chance to read the cold water temperature and then start the engine Here it is "When it's cold I heard it helps to turn the key to the first position (when all the dummy lights illuminate) and wait about 10 seconds before turning to the start position. This supposedly allows the sensors to adjust for the cold and it runs better."




Cold engines might experience problems at the time to start due to different reasons. One of these reasons can be based on the effect which cold has on liquids evaporation. When it is cold, gasoline evaporates less and this cause it to be more difficult to burn due to the fact that it is burnt when it is evaporated.

Another reason by which a cold engine might have problems to start is caused by the fact that oil becomes much thicker in cold than the way it is in hot. Oil, like any other liquid changes its consistency when it is exposed to very low temperatures as well as it changes back when it is in a very hot weather, and this might cause oil to have problems at the time of circulating in the car engine.

Besides the engine, car batteries might experience problems while being in cold weathers as well and this could affect the engine. Batteries function through chemical reactions which loose agility while being cold and therefore, in such circumstances, batteries don't function properly. When this happens, the car energy becomes affected and this causes problems for the engine start.

If these three problems happen together, starting an engine might become a really hard task to achieve. In order to overcome the lack of gasoline evaporation problem, you can spray ether into the engine which would evaporate quickly and help the engine start. Besides this, you can also to prevent having oil too thick which wouldn't circulate properly by using thin synthetic oils. You should also try to maintain the car isolated from cold as much as possible, but by using the two last mentioned methods you would experience much less problems at the time of staring the car in cold weather.
john

[taksepidar]

my guess
1-Idle speed motor

2- CTS(Cooland temperature sensor ) sensor maybe it always show the engine is hot while it is not, you can easily test this sensor with ohmmeter