2002 Stalls After Starting In Cold - Toyota Corolla, Chevy Prizm (1998-2008)

When it is REALLY cold the car starts but then stalls like a seconds after releasing the key.

(And no I'm not releasing the key too soon - it starts and is going then release the key and it stalls. It didn't used to do this).

When it was quite cold (-30C) it did this a couple times in a row for example, then it started finally and ran all weird for a few seconds and I heard really rough scary sounds from engine, though they were sort of mechanical sounds.

Pressing the gas didn't even cause the RPMs to increase it just ran really rough for a bit. Then it went back to normal normal.

I've noticed that the engine seem to be more noisy and the streering wheel can even vibrate when cold, it didn't use to do this. Seems OK when warmed up. Just engine sounds noisier I think, sort of rattly a bit.

Now with the weather not too cold (-10C) its starts fine, but it almost seems like there is a weird skip or pause still right after you let go of the key. It is like that is the time that it would stall when it is colder, but it is just sort of seeming to drop rpm or sort of start strange...

Shop said should change the tensioner - but I took off the belt and spun it by hand and it is all smooth feeling, it doesn't feel bad ??

Shop said they did a compression test and the motor is fine.

A couple times now after starting the car I can smell gasoline for about 15 seconds.

What does that mean? I will have to see if this happens again to confirm this is really happening.

If so what does that mean?

At those temps - I'm not surprised that the engine was acting the way it was. What oil viscosity are you running, synthetic motor oil? Part of the starting issue is the returnless fuel system on the car - the fuel pump only sends fuel when needed, this can cause periods where the engine seems to crank longer than usual before it fires. If you get the engine to catch and it immediately dies afterwards - pull hte plugs and double check that they are still in good shape. Double check the plug gap and chassis grounds on the engine (just trace back all the ground lines - from the negative battery terminal). The 1ZZ-FE is pretty sensitive to plug gap and electrical noise. At those temps, it is possible that you have intermittent ground connectivity that is confusing the ECM.

The gasoline odor, especially if the car is taking more than the usual number of cranks before it fires up, is normal. The ECM is commanding more fuel to be sent to help start the engine. If the engine initially stalls or dies on the first attempt, fuel will still be loaded in the cylinders, sometimes to the point where they foul the plugs (they become saturated with fuel) and subsequently harder to restart. Only atart worrying when the fuel odor happens every time you startup the car, regardless of ambient temps. Then you could be looking at a leak somewhere.